This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Can't send e-mail through Thunderbird

  • 4 ŋuɖoɖowo
  • 3 masɔmasɔ sia le wosi
  • 1 view
  • Nuɖoɖo mlɔetɔ DennisA

more options

When I try to send messages through Thunderbird for my comcast e-mail accounts I get the following message:

Sending of the message failed. An error occurred while sending mail: Outgoing server (SMTP) error. The server responded: resomta-h1p-027912.sys.comcast.net resomta-h1p-027912.sys.comcast.net Excessive failed authentication, ESMTP server temporarily not available, please contact support.

I've checked with XFinity (Comcast) and things are working normally on their end. In fact I can send messages using the web access just fine. It's only using Thunderbird that I get this message.

When I try to send messages through Thunderbird for my comcast e-mail accounts I get the following message: Sending of the message failed. An error occurred while sending mail: Outgoing server (SMTP) error. The server responded: resomta-h1p-027912.sys.comcast.net resomta-h1p-027912.sys.comcast.net Excessive failed authentication, ESMTP server temporarily not available, please contact support. I've checked with XFinity (Comcast) and things are working normally on their end. In fact I can send messages using the web access just fine. It's only using Thunderbird that I get this message.

Ŋuɖoɖo si wotia

OK, So I went back to my original settings and now things are working. I don't think this was a setting issue but was triggered by changing my comcast passwords per their notice that they were compromised. The comcast server started re-sending the e-mails I had already been sent and because at least one input e-mail address triggered sending out copies of the e-mail to three other people it was triggering a failed password on the outgoing e-mails a large number of times.

Per the original error message all those failed password messages must of triggered comcast to suspend my outgoing e-mails.

I called them first and they suggested it was a Mozilla issue. So it's a story of one company pointing fingers at another.

Because Thunderbird doesn't allow you to use the application to go in and change the passwork for incoming and outgoing at the same time, things like my set up will trigger a large number of failed password attempt.

Xle ŋuɖoɖo sia le goya me 👍 0

All Replies (4)

more options

What are your settings? Comcast recommends:

smtp.comcast.net on 587, STARTTLS security, authentication = normal password, User Name = email address

https://www.xfinity.com/support/articles/email-client-programs-with-xfinity-email

Note that performance with webmail is generally unrelated to performance with POP, IMAP and SMTP servers in mail clients.

more options

I've been using what Comcast said to use for a long time. Did things change? I'm using POP and using mail.comcast.net with Port 995. Using SSL/TLS and Normal Password on the input side.

On the Output side I'm using smtp.comcast.net with a Port of 465, Normal Password, and SSL/TLS

The error message however seems to indicate Excessive Failed Authentication which seems different than the Port and Password information.

I've been using my settings since at least 2020 which is why I asked if the settings have recently changed.

more options

Just to be sure, I changed to your output settings and got the following message:

Sending of the message failed. The message could not be sent because connecting to Outgoing server (SMTP) smtp.comcast.net failed. The server may be unavailable or is refusing SMTP connections. Please verify that your Outgoing server (SMTP) settings are correct and try again.

more options

Ɖɔɖɔɖo si wotia

OK, So I went back to my original settings and now things are working. I don't think this was a setting issue but was triggered by changing my comcast passwords per their notice that they were compromised. The comcast server started re-sending the e-mails I had already been sent and because at least one input e-mail address triggered sending out copies of the e-mail to three other people it was triggering a failed password on the outgoing e-mails a large number of times.

Per the original error message all those failed password messages must of triggered comcast to suspend my outgoing e-mails.

I called them first and they suggested it was a Mozilla issue. So it's a story of one company pointing fingers at another.

Because Thunderbird doesn't allow you to use the application to go in and change the passwork for incoming and outgoing at the same time, things like my set up will trigger a large number of failed password attempt.