How did they determine that? Did they try with the same profile?

Correct - they used my same profile against each version.

Then I don't see how two versions could behave differently wrt the user ID. What exactly is the problem with 38.6.0? Do you get any error message? Is a personal firewall or security software blocking Thunderbird (e.g. like Norton)?

Assuming there were not changes on the Thunderbird side, I agree. All previous upgrades were seamless.

I receive the following error message:

Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) smtp.onebox.com timed out. Try again.

Are there any configurations I should be concerned about?

Is your complete username in the field for your SMTP settings?

Please answer all questions. https://support.mozilla.org/en-US/questions/1111870#answer-849412

Q: Is your complete username in the field for your SMTP settings? A: I don't see a place to enter a username for the "Outgoing Server (SMTP)" window, I only see that in the "Server Settings" window. If you meant the "Server Settings" window, I have the User Name field filled with the username I use when I directly log into my Onebox.com account (ex. xxxxxx@onebox.com).

Q: Is a personal firewall or security software blocking Thunderbird (e.g. like Norton)? A: I changed from McAfee to Bitdefender about one year ago and was able to send emails afterwards. If there is a setting within Bitdefender I should be checking to confirm if it is blocking me from sending email, pleeease let me know (I haven't changed any settings since the initial install that wasn't posing any problems sending emails through Thunderbird).

Right click the account on the left side in the Folder Pane. Select Settings Go to the bottom of that list to Outgoing Server (SMTP) That is where you edit smot server settings.

My "Outgoing Server (SMTP)" has a single identity, with the following settings:

Server Name: smtp.onebox.com Port: 587 User Name: xxxxxxx@onebox.com Authentication method: No authentication Connection Security: None

Port 587 usually uses connection security of STARTTLS and requires a password.

You might double check the SMTP settings that your provider uses.

Airmail -

After thinking about your comment regarding the Port #, I recalled that at one point I was using Microsoft Outlook. I checked the configs there and determined that my port was incorrect! I changed the port and I'm up and operating again! Thanks sooo much! I'm not sure why Onebox so poorly misdirected me.

Thanks again!

I'd really be curious how your ISP concluded the problem is caused by the wrong user ID format. In any case, when your problem is fixed, can you mark the thread as 'Solved' please? Thank you.