OK, you are talking about messages sent to you?

So, under what circumstances do you see a message about "mail being returned by server"? That doesn't sound like a message a server would raise in response to an attempt to collect email.

Are the people sending to you seeing this message? If you are seeing it then it's possible you're connecting to a server responsible for sending when you need one that handles receiving.

Go to Help|Troubleshooting Information in Thunderbird. Un-tick the checkbox labelled "Include Account names" Click on "Copy text to clipboard" Open a reply here. Paste in the information from your clipboard. (ctrl+v on the keyboard, or right-click|Paste with the mouse.)

You can select everything from and below "font.default:" and delete it, as it's not relevant here.

I emailed the person who sent me the email, they told me that they got back all of the ones they had sent me marked returned as spam. I didn't see any of them. I didn't find the troubleshooter information on my email so I could not do that.

That would suggest that your provider is running a spam system that returns messages to your correspondents becasue it thinks they are spammers.

Nothing to do with your Thunderbird.

Now, hold down the <alt>, tap H then select Troubleshooting Information.

Zenos said

That would suggest that your provider is running a spam system that returns messages to your correspondents becasue it thinks they are spammers. Nothing to do with your Thunderbird. Now, hold down the <alt>, tap H then select Troubleshooting Information.

I did what you said to do but I have no idea what to do from there. But it sounds like to me you are telling me that it is my server that is doing wrong.

barebare said

Zenos said

That would suggest that your provider is running a spam system that returns messages to your correspondents becasue it thinks they are spammers. Nothing to do with your Thunderbird. Now, hold down the <alt>, tap H then select Troubleshooting Information.

I did what you said to do but I have no idea what to do from there. But it sounds like to me you are telling me that it is my server that is doing wrong.

barebare said

Zenos said

That would suggest that your provider is running a spam system that returns messages to your correspondents becasue it thinks they are spammers. Nothing to do with your Thunderbird. Now, hold down the <alt>, tap H then select Troubleshooting Information.

I did what you said to do but I have no idea what to do from there. But it sounds like to me you are telling me that it is my server that is doing wrong.

barebare said

Zenos said

That would suggest that your provider is running a spam system that returns messages to your correspondents becasue it thinks they are spammers. Nothing to do with your Thunderbird. Now, hold down the <alt>, tap H then select Troubleshooting Information.

I did what you said to do but I have no idea what to do from there. But it sounds like to me you are telling me that it is my server that is doing wrong.

 Application Basics

   Name: Thunderbird
   Version: 31.3.0
   User Agent: Mozilla/5.0 (Windows NT 6.1; rv:31.0) Gecko/20100101 Thunderbird/31.3.0
   Profile Folder: Show Folder

             (Local drive)
   Application Build ID: 20141127140543
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory

 Mail and News Accounts
   account1:
     INCOMING: account1, , (pop3) mail.nts-online.net:995, SSL, passwordCleartext
     OUTGOING: mail.nts-online.net:587, alwaysSTARTTLS, passwordCleartext, true

   account2:
     INCOMING: account2, , (none) Local Folders, plain, passwordCleartext

 Crash Reports

 Extensions

 Important Modified Preferences

   Name: Value

     accessibility.typeaheadfind.flashBar: 0
     browser.cache.disk.capacity: 358400
     browser.cache.disk.smart_size.first_run: false
     browser.cache.disk.smart_size.use_old_max: false
     browser.cache.disk.smart_size_cached_value: 358400
     extensions.lastAppVersion: 31.3.0

Your settings look fine. And what you've said about people sending to you does suggest the trouble lies with the email provider and their system rejecting your frends' messages as Spam.

Thunderbird can't refuse delivery, and it doesn't use the word "Spam". So, IMHO and AFAIK, messages being thrown back to the original senders and labelled as "Spam" can only come from a server.

Zenos said

Your settings look fine. And what you've said about people sending to you does suggest the trouble lies with the email provider and their system rejecting your frends' messages as Spam. Thunderbird can't refuse delivery, and it doesn't use the word "Spam". So, IMHO and AFAIK, messages being thrown back to the original senders and labelled as "Spam" can only come from a server.

Thank you for the help, and sorry I was so slow. barebare