Sending failing: ESMTP error?

[Flycaster]

Windows 10 21H1, Thunderbird 91.5.0 64-bit.
All of a sudden, sending emails are failing with the following ESTMP error:

"An error occurred while sending mail: Outgoing server (SMTP) error. The server responded: resomta-h1p-028516.sys.comcast.net Excessive failed authentication, ESMTP server temporarily not available."

This Xfinity link appears to explain what is happening (The answer: https://forums.xfinity.com/conversation ... 01ee5e947f). As I seem to be having the same problem as the OP of this link (getting the same error message when sending an email and being able to send emails directly from Xfinity but not from third party--Thunderbird,) the problem is with Thunderbird's sending "...incorrect authentication credentials to our server too many times at which point our server will block any further attempts from ANY device until the refresh interval..."

I do not send excessive emails, nor have I tried emailing after Xfinity's "refresh interva" (which could be later today). Anyway, how is this problem to be solved as it lies within Thunderbird? Thanks.

[tanstaafl]

I just sent a message from my Comcast IMAP account using TB 91.5.0 64 bit under Windows 10 Home 21H2. No problems.

The thread you linked to basically claims the server responded to too many failed login attempts by setting a timer before it would let you try again. The question is why do you have any failed login attempts at all, and why don't you have problems checking for new mail?

It handy to have at least two accounts (from different email providers) because if one account has problems sending you can temporarily re-configure it to use the other accounts smtp server. I suggest you try that and see if that works around the problem. If it does that seems to rule out Thunderbird being the culprit.

[Flycaster]

Believe me, I haven't done excessive emailing at all and have not had problems when signing in. Can't understand why this is happening. Although early this morning, I was able to send an email. Sending emails early in day has been reported by others who have had a similar problem. So, you are suggesting that aside from Comcast, I should add another email server like gmail? If so, is there a tutorial for this? Thanks.

[DanRaisch]

See if this article is helpful -- https://support.mozilla.org/en-US/kb/th ... -and-gmail

Another option for a free email account to use when troubleshooting (or just for general use would be Hotmail/Outlook -- https://support.mozilla.org/en-US/kb/th ... nd-hotmail

[Flycaster]

Thanks, Dan. Actually, I was able to send an email just now. So, maybe, this problem has resolved. However, if the issue rears its ugly head again, I certainly will look into your suggestions. And, BTW, I can always send emails via Comcast on the net.