Xfinity will block everything if you have not selected to allow third party programs like Thunderbird, access to the server. Please use the information at the following link to check this option has been selected: https://www.xfinity.com/support/articles/third-party-email-access

I've included an image below as a guide.

It would also be useful if you could post the following information. Please let us know if you are still connecting to a comcast email address.

• Account Settings > Server Settings for the account.
• upload an image showing all the server settings.

We need to check you have correct server settings and have not mixed up pop and imap settings.

• Account Settings
• Select name of account in left pane
• bottom right click on 'Edit SMTP Server' button
• upload an image showing the smtp settings you are using.

Thanks for taking an interest, Mr. Hall. On the Xf portal, this neophyte can't start Xf email...I cant even create an account (see below), so I can't click thru to Security to uncheck/check Third Party Access Security. If I use the Xf portal to "check email" I get the useless notice called "Using and managing Xf email accounts", which states that "since last June new Xf customers can't create an Xf email (Comcast.net) account." It then states I can use third party email accounts to manage my Xf account. That would be fine, except Thunderbird is my 3rd part account!

Here are my screen shots...

This is true - Comast/Xfinity is passing their email service on to Yahoo, and after a certain point they will not let new customers create new comcast.net email boxes. Those of us who are long-time customers will supposedly get to keep our comcast.net addresses, though the service itself will be hosted by Yahoo. I don't know exactly when or how this is supposed to happen, but it sounds like you've gotten caught in the transition. There has been little direction from Xfinity itself.

Coincidentally, maybe... Comcast's IMAP service has been flaky since last night. First it was very slow, then it was not working at all, then it worked, then it didn't, now it works but it's very slow. Maybe we're in the middle of the big change.

When you were with Spectrum, a 'roadrunner.com' email address should have been using the following server settings for a Pop account:

• POP server name : mail.twc.com
• port: 995
• Connection Security: SSL/TLS
• Authentication Method: Normal Password
• username :full email address
• Password - same one you use to access webmail account.

• SMTP server name : mail.twc.com
• port: 587
• Connection Security: STARTTLS
• Authentication Method: Normal Password
• username :full email address
• Password - same one you use to access webmail account.

So, it seems very odd that you appear to be using very old server settings.

I would first try changing the server settings to the ones mentioned above - then restart Thunderbird.

It looks like you have two accounts, usually you need two smtp because whilst server settings might be the same the username = full email address and the password is usually different. But I do not know how the second account is set up.

Query: Have you enabled a VPN?

Also check any Anti-virus product you use, because many now offer a VPN and in some cases they have enabled it by default. Servers do not like VPN because it hides your IP address and makes it look like you are a hacker, so server tend to block access, so please double check your computer and disable/switch off VPN.

rednoise is correct about comcast being moved to yahoo.

This link offers more info and I suggest you give it some attention. https://www.xfinity.com/support/articles/yahoo-email-migration-overview

Have you had any communication regarding this?

When logon to xfinity - try this link: https://www.xfinity.com/support/articles/sign-in-to-customer-central Then scroll down, look for the following line and click on the text that says 'Sign in to your Xfinity Email' : "Trying to access your Xfinity Email account instead? Sign in to your Xfinity Email "

As that login specifically says comcast.

It might also be a good time to consider getting yourself a free email address that's not specific to your ISP, such as gmail etc.

This link discusses the server settings you will need to use when you have moved to Yahoo: https://help.yahoo.com/kb/new-yahoo-mail/SLN36803.html

yahoo do have their own querks and one of them relates to passwords. Yahoo tend to insist on using an app generated password for third party apps like Thunderbird. So whilst a normal password allows to logon to webmail, in Thunderbird when it asks for password you would enter the app generated password - and that means it can only be used for that email address. If you have several email addresses using yahoo server then you may need one per email address. But that's a different hurdle - I'm just giving you a heads up.

Toad-Hall you are my savior. All is well in my version of Xfinityland for now. Your 8:41 AM response led directly to a solution. I wii certainly be following up with your additional advice as well.

Thanks again for timely and laser-guided responses.