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Thunderbird no longer configures with Xfinity

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-I'm using Ubuntu 14.04. -In November, 2018, Comcast/Xfinity changed a few of their email settings, eg POP3 port 110 changed to 995. They also mentioned that they prefer we don't use POP3 any more. It's moot, though! -In November, I suddenly stopped being able to receive. I've had their tech people help me set up as either POP3 or IMAP and neither works. After an hour (over two hours yesterday) they always end up saying it's Mozilla's problem. -I've uninstalled Thunderbird several times, including deleting hidden files that contained remnants. -I usually get the message ""Thunderbird failed to find the settings for your email account." -Other attempts give me "Configuration could not be verified - is the username or password wrong?", or "User name or password invalid." That is wrong! -On Xfinity's site, I can both send and receive directly from there. They claim this proves the problem is with you. -I'm suspicious that Comcast/Xfinity has changed their setup and Thunderbird hasn't been updated.

-I'm using Ubuntu 14.04. -In November, 2018, Comcast/Xfinity changed a few of their email settings, eg POP3 port 110 changed to 995. They also mentioned that they prefer we don't use POP3 any more. It's moot, though! -In November, I suddenly stopped being able to receive. I've had their tech people help me set up as either POP3 or IMAP and neither works. After an hour (over two hours yesterday) they always end up saying it's Mozilla's problem. -I've uninstalled Thunderbird several times, including deleting hidden files that contained remnants. -I usually get the message ""Thunderbird failed to find the settings for your email account." -Other attempts give me "Configuration could not be verified - is the username or password wrong?", or "User name or password invalid." That is wrong! -On Xfinity's site, I can both send and receive directly from there. They claim this proves the problem is with you. -I'm suspicious that Comcast/Xfinity has changed their setup and Thunderbird hasn't been updated.

Isisombululo esikhethiwe

Matt, I checked this, and mine was already set to "false," by default. But what the heck, I changed it to "true" just for kicks... And it worked! Thank you so much!! That's quite a discovery on your part, even if it did turn out to be the opposite of what worked in my case. It's worked several times now, so far. Thank you again, I really appreciate your help!

Funda le mpendulo ngokuhambisana nalesi sihloko 👍 0

All Replies (10)

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I note you mention 'comcast' and Linux. there have been several reports at the moment regarding this.

Sounds like comcast are having some issues.


I did locate info where someone also using Linux got a hint to change the IMAP server name from imap.comcast.net to imap.ge.xfinity.com

quote: For those looking for a more direct answer, name resolution for imap.comcast.net seems to be failing recently. Users in the Ubuntu forum thread offer the resolution of changing the account's server to one of the IP addresses reported by "nslookup imap.comcast.net" (use the terminal, Luke.) Rather than using a fixed IP address, I reset the server name to imap.ge.xfinity.com (the canonical name for imap.comcast.net) then had to submit my password for the newly-named server. Works a treat.

Try changing the server name and report back on results. I've advised others in your situation to change the server and it has been successful in their cases.

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Thanks to the people who responded above. I tried the nslookup imap.comcast.net idea, but it didn't change anything. Still getting the message "Configuration could not be verified - is the user name or pw wrong?" Also, at other times, "!User name or password invalid" and "Configuration could not be verified - is the user name or PW wrong?" Yet, I can send and receive at their site online. This began a week ago with me only able to send. Now I can't do anything. And originally, I wanted to keep my incoming as POP3. Comcast changed the port # for that in November from 110 to 995. I thought that was the problem, but now nothing works, not even IMAP. After more than 2 hours on the phone with them yesterday, my brain's still numb. I'm not fighting this anymore for a few days, I'm too busy this month. If I eventually find an answer, I'll post it here. Thanks again.

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re :I tried the nslookup imap.comcast.net idea,

Did you reset the account's server name to imap.ge.xfinity.com and provide password at prompt?

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Sorry, I should have mentioned that server name would not work for POP. You would need to set up new existing mail account as imap and use the server name imap.ge.xfinity.com.

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Hi Toad-Hall, I tried the imap.ge... suggestion, as imap, not POP3, and got a warning message: "You are about to override how Thunderbird identifies this site.

Legitimate banks, stores, and other pulbic sites will not ask you to do this."

Certificate Status: This site attempts to identify itself with invalid information." Wrong Site: The certificate belongs to a different site, which could mean that someone is trying to impersonate this site." ... So I cancelled out. It also says the organization is COMODO, so if that's the firewall firm, they need to fix something, as well! Anyway, I easily got a gmail account to work, so until I can get some actual time to think straight, I'll just use it in Thunderbird. Thanks again, and I'll check back in in the future with anything I might discover.

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I'm out of ideas. I've basically only repeated the same steps, though, because I have no other ideas and can't find any. Comcast can't provide a proper setup, and Mozilla has no ideas, and I don't care what that COMODO thing was, I'm obviously not going to override a security warning. I'm disgusted with everything right now, and am considering a switch to Frontier's internet service. Thanks again for the ideas.

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based on something in another thread. try changing network.dns.disableIPv6;true in the config editor apparently ipV6 is a mess and is enabled by default. There an not many ipV6 networks out there for mail.

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re :COMODO thing sounds like your Anti-Virus is producing this.


comcast is causing a load of issues. some people have allowed the exception. Some people have found with ubuntu that they needed to reinstall libnss-resolve.

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Isisombululo Esikhethiwe

Matt, I checked this, and mine was already set to "false," by default. But what the heck, I changed it to "true" just for kicks... And it worked! Thank you so much!! That's quite a discovery on your part, even if it did turn out to be the opposite of what worked in my case. It's worked several times now, so far. Thank you again, I really appreciate your help!

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Toad-Hall, I just posted a response but it didn't appear, so I'll try again: It's not an antivirus thing. Since I'm using Linux, there's no antivirus running. The links you sent have some good info, though. I thought I was a good researcher, yet I never came across those in the xfinity forum. I was too overwhelmed. Thanks again! You're right about Comcast! When things run well, they're great. When things break down, you enter a Hellscape of problems.

But it looks like this was not Comcast's fault, unless it was their system that set network.dns.disableIPv6 wrongly. Now with Matt's apparent solution, I'm going to pass the info on to Comcast - I hope it doesn't end up lost on some poor, over-worked, low-wage Third World phone worker's note pad.