I forgot to include the Suddenlink (ISP) settings. Here they are:

Connect Email to POP or IMAP

Category: Internet

Check your email online via our webmail platform or through your third party email client. If you would like to use a third party email client to access your Suddenlink email, please use the settings listed below.

What is the difference between IMAP and POP? IMAP (Internet Message Access Protocol) is a popular protocol that keeps your email on the server and always synchronized across all your devices. For example, if you delete, send or mark a message as unread on one device, it is reflected on all your devices. IMAP is recommended for those who check their email on multiple devices since it provides a more consistent experience across all devices.

POP (Post Office Protocol) downloads your email onto your device. Therefore, actions on one device are not reflected on other devices. Using the same example, if you delete, send or mark a message as unread on one device, the changes will not be reflected on other devices. If you access your email on multiple devices, IMAP is the recommended option.

Email Settings Here are the settings you will need to set up your email client, whether you prefer to use IMAP or POP.

IMAP (inbound) Incoming Mail Server: imap.suddenlink.net
 Incoming mail port (SSL): 993 (Secure Connection. Recommended if your email client supports) Incoming mail port: 143
 (Not recommended. Legacy mail clients only)

POP (inbound) Incoming Mail Server: pop.suddenlink.net 
Incoming mail port (SSL): 995 (Secure Connection. Recommended if your email client supports) 
Incoming mail port: 110 (Not recommended. Legacy email clients only)

SMTP (outbound) Outgoing Mail Server: smtp.suddenlink.net
 
Outgoing mail port (SSL): 465 (Secure Connection. Recommended if your email client supports) Outgoing mail port: 25 or 587 (Not recommended. Legacy email clients only)

Username & Password Username: your full email address, including the @domain.net at the end (i.e. @suddenlink.net) Password: The password set to your particular email address

Note: Outgoing server verification/authentication must be enabled and on. If your email client has the option or checkbox that says My outgoing server requires authentication this will need to be checked along with use same settings as my incoming mail server.

If the email client asks for Clear Text Authentication, check yes.

The settings above are good for the below domains:

@suddenlink.net - Residential Suddenlink Accounts @suddenlinkmail.com - Commercial Suddenlink Accounts @npgcable.com - no longer available for creation @stjoelive.com - no longer available for creation @uneedspeed.net - no longer available for creation @ponyexpress.net - no longer available for creation @magiccablepc.net - no longer available for creation @cebridge.net - no longer available for creation @classicnet.net - no longer available for creation @kingwoodcable.net - no longer available for creation @kingwoodcable.com - no longer available for creation @usamedia.tv - no longer available for creation @tyler.net - no longer available for creation

If your sent messages are copied to the Sent folder without error, the mail has reached your smtp server, so if it's not received at the other end, it's possibly due to the recipient's mail provider blocking mail from suddenlink because of abuse by someone sending from the suddenlink domain. You would have to contact the recipient's provider to ask if or why suddenlink is on their blacklist.

You should also ask recipients to check their Spam/Junk/Bulk folders in case your messages have been routed there due to false positive spam detection, e.g. your mail has a lot of links or remote content. Those folders aren't visible with POP setups - they can be viewed through IMAP setups or through webmail.

Note that some providers like gmail don't show mail sent to oneself, and with suddenlink they might be sent to spam (which you can't see with POP).

Thanks for your suggestion. I logged onto the webmail page of suddenlink.net and sent 6 test emails to 6 separate domains: gmail.com, sbcglobal.net, yahoo.com, Wycliffe.org, aol.com, and att.net. Each of the people received my emails. If I understand the system correctly, since the web server sent the emails and they were received, that means that Suddenlink is not being blocked by other domains. In other words, the recipient's mail provider is not blocking the suddenlink domain.

Today I sent a "Reply" from Thunderbird with a cc to me. I got the cc message. Then I sent a composed email from Thunderbird to myself and it has not gone through.

That brings us back to the original unsolved question. What needs to be done so I can send emails?

Thanks for your help.

Keep in mind that sending through webmail is not exactly the same as sending through the suddenlink smtp, as the latter could still be blocked even when webmail is not. As mentioned before, try to get your recipients to check their Spam folders in case your messages were sent there. Also, ask suddenlink if they have received reports from other customers trying to send over smtp (not webmail).

You might try sending from another program, such as the Apple Mail app, to see if it's an smtp issue or a problem with TB. If it turns out that you can't send with any mail app, consider adding a gmail or similar account and then configuring the suddenlink account to send through the gmail etc. smtp.

Thanks for the latest reply. I am confused, though. Hopefully, someone can help.

The reply above dated Feb 24 states "If your sent messages are copied to the Sent folder without error, the mail has reached your smtp server, so if it's not received at the other end, it's possibly due to the recipient's mail provider blocking mail from suddenlink because of abuse by someone sending from the suddenlink domain. You would have to contact the recipient's provider to ask if or why suddenlink is on their blacklist."

In the reply above dated Feb 25 at 11:00 am, the comment was made "Keep in mind that sending through webmail is not exactly the same as sending through the suddenlink smtp, as the latter could still be blocked even when webmail is not."

That's why I sent several separate emails from the suddenlink webmail to make sure the emails were not being blocked by other domains. The fact that they went through, means that the suddenlink emails are not being blocked.

I do not understand how a message posted in the Sent folder without error means that the "mail reached the smtp server" but if it is sent via webmail, that is somehow different. This implies that the suddenlink smtp blocks the TB sent file but it tells TB that is was really sent and accepted. Those two ideas seem to be contradictory to me.

My recipients never had an issue receiving my emails prior to mid-December. Therefore, I don't see how messages would suddenly appear in their Spam folders now. Also, one of my main recipients does not have my emails appearing at all. Something has to have happened to ALL my recipients to keep them from getting my emails.

I'll try Apple Mail once again to see if the emails get sent. If they are not received, then does that mean that there is, in fact, an issue with TB? I do not want to use gmail, Apple mail, or any other webmail server. I want to continue using TB, if at all possible.

legvidal said

Thanks for the latest reply. I am confused, though. Hopefully, someone can help. The reply above dated Feb 24 states "If your sent messages are copied to the Sent folder without error, the mail has reached your smtp server, so if it's not received at the other end, it's possibly due to the recipient's mail provider blocking mail from suddenlink because of abuse by someone sending from the suddenlink domain. You would have to contact the recipient's provider to ask if or why suddenlink is on their blacklist." In the reply above dated Feb 25 at 11:00 am, the comment was made "Keep in mind that sending through webmail is not exactly the same as sending through the suddenlink smtp, as the latter could still be blocked even when webmail is not." That's why I sent several separate emails from the suddenlink webmail to make sure the emails were not being blocked by other domains. The fact that they went through, means that the suddenlink emails are not being blocked.

No, that shows suddenlink mail is not blocked when sent from webmail, it doesn't prove anything about mail sent through smtp.

I do not understand how a message posted in the Sent folder without error means that the "mail reached the smtp server" but if it is sent via webmail, that is somehow different. This implies that the suddenlink smtp blocks the TB sent file but it tells TB that is was really sent and accepted. Those two ideas seem to be contradictory to me.

Mail isn't copied to Sent if it's rejected by the suddenlink smtp. The problem is that the recipient's server is rejecting mail sent from suddenlink's smtp. Sending from webmail is not the same as sending from a mail app on smtp.

My recipients never had an issue receiving my emails prior to mid-December. Therefore, I don't see how messages would suddenly appear in their Spam folders now. Also, one of my main recipients does not have my emails appearing at all. Something has to have happened to ALL my recipients to keep them from getting my emails.

Something must have changed since then, either with suddenlink's smtp or suddenlink's blacklist status with other providers. Still no answer as to whether your recipients have checked folders other than Inbox.

I'll try Apple Mail once again to see if the emails get sent. If they are not received, then does that mean that there is, in fact, an issue with TB? I do not want to use gmail, Apple mail, or any other webmail server. I want to continue using TB, if at all possible.

If your mail isn't received with other apps, it suggests the problem lies with factors beyond TB or any mail app. If it works with Apple Mail, there's a good chance the problem is with TB.

Thanks for the updates above.

I composed 5 emails and sent them in Apple Mail: suddenlink.net, yahoo.com, jaars.org, gmail.com, and sbcglobal.net. All appear in the "Sent" folder in Apple Mail. None of the items appear in the Inbox of Apple Mail. For some reason, Apple Mail can not retrieve any emails.

All 5 emails were received from Apple Mail by the recipients. They responded to me and those emails appear in Thunderbird in the Inbox folder.

Thanks.

Here are some other items to consider.

When I click on Reply within TB, sometimes the message gets to the recipient. Other times it does not make it. Why is this? When I compose an email within TB, it does not make it to the recipient.

If there is something I can change in TB to solve this issue, please let me know. I can not find anything to change.

If there is something in Mac OS 10.15.3 that I can change, please let me know. I read that sometimes a firewall will stop outgoing mail. However, as far as I know, the only firewall I have is built into the Mac OS. I can not find anything to change in the firewall.

TB is listed in the section for "Full Disk Access". It has a checkmark by it. I assume this is correct. However, I don't know for sure. I did read an article online about sometimes the OS does not recognize the current version of TB and may not work with it. I do not know if that is the case here or not. I can not find any information to find out.

Thanks so much for your help.

You are a mac user, experience tells me you probably using a signature on your emails, It almost goes with owning a MAC. One that you are unlikely to be using on web mails that work.

The vast majority of mail send and not received is because the mail is detected as spam at the receiving end. You could be sure is Suddenlink were to access their server logs and confirm they sent the mail on, but for some reason it can be difficult to convince mail providers to do more than offer platitudes and transfer blame.

Thunderbird sends mail in a very old manner. It contact the server and makes you wait until is either gets an OK from the server or an error. If the dialog saying sending has gone away and no error message appeared to replace it, Thunderbird has handed the mail off to Suddenlink for them to do their part.

Like dropping a mail in the letter box on the side of the road, Thunderbird offered it, and stood and waited to make sure it went in the flap. Now it trusts the post office (Suddenlink ) to actually deliver the mail. Email, like snail mail before it actually only offers a best effort to deliver, not a guarantee.

It is the lack of a guarantee that makes things murky. Due to the amount of SPAM and the user demand to "only see the mail they want" providers enable some bizarre methods for sorting out spam. There are no rules and all sorts of things like hanging up on the sever trying to make the delivery for the first three times they connect are becoming common. Likewise they analyze the content of the email and if it is meeting their definition of spam that they invented they just don't deliver the mail. This is often caused by social media graphics in the signature as they are also most likely picked up from the internet and have been used in actual SPAM, or the ratio of graphics to text in the message can be a trigger. Having a graphics with text on it can also lead to "graphics spam" labels. So you are asking here for a "real reason" but unfortunately as this is a part of the game that has no rules, all anyone can do is guess.

Another common issue is sending mail from say a comcast account from an ATT SMTP server.

I suggest you look in your outgoing servers SMTP and ensure you only have the two listed. It might be when you click reply on some mail that the outgoing server used for that account is not what you think it is. Especially if the mail is being picked up at the server level from another account. having gmail collect mail to say a suddenlink account and then replying from the gmail account is something that would get some spam filters very excited.

Thanks for your reply.

"You are a mac user, experience tells me you probably using a signature on your emails, It almost goes with owning a MAC. One that you are unlikely to be using on web mails that work."

If I understand signatures on emails correctly, I have not used an email signature in several years. A screen print from TB is attached. It shows not signature is being used.

"I suggest you look in your outgoing servers SMTP and ensure you only have the two listed. It might be when you click reply on some mail that the outgoing server used for that account is not what you think it is. Especially if the mail is being picked up at the server level from another account. having gmail collect mail to say a suddenlink account and then replying from the gmail account is something that would get some spam filters very excited."

I only have 2 outgoing SMTP servers, both of which are smtp.suddenlink.net with separate suddenlink.net email addresses. I have used these for years. I have never used gmail or other webmail servers. S screen print showing the smtp servers is attached.

"The vast majority of mail send and not received is because the mail is detected as spam at the receiving end. You could be sure is Suddenlink were to access their server logs and confirm they sent the mail on, but for some reason it can be difficult to convince mail providers to do more than offer platitudes and transfer blame."

I agree with your assessment of the difficulty of convincing mail providers. The tech support people at suddenlink will only answer questions for their webmail server. They will NOT help at all with 3rd party clients like TB. I've sent many requests to suddenlink and have not received a response from them.

By the way, my challenge sending emails (mainly composing new ones) started in mid-December 2019. See the earlier details in this question. Now no one can receive my emails sent through TB. Since NO ONE can receive the emails, I don't think the issue is with spam at the receiving end. See the earlier details on the emails I've sent in test mode to resolve the various items suggested -- 6 separate domains: gmail.com, sbcglobal.net, yahoo.com, Wycliffe.org, aol.com, and att.net.

I think the rest of your response concerns the challenges with hitting "Reply" within TB. FYI, the "Reply" button has worked just fine the past 2 or 3 days. Thanks so much for the explanation. Unfortunately, the issue of sending new composed emails has not been resolved. That's why I added some extra things to consider on Feb 26, 2020 in case that will help solve this issue.

Thanks once again.

Attached are 2 screen prints to go with my "2 outgoing smtp servers" comment on Feb 28, 2020. Thanks.