I'm also having issues using Thunderbird with Spectrum mail servers. In my case, I'm on the mail.twc.com server, and I am using IMAP. My problem involes getting new messages. Thunderbird isn't properly syncing with the Spectrum servers.
After working on it here, and then taking it to the Mozilla Thunderbird forum, I'm begining to think there are some major compatability issues between Thunderbird and the way the Spectrum servers are configured.
It has got to be some incompatibility between Thunderbird and the mail.twc.com servers. I installed a fresh copy of Thunderbird on a different Windows 10 machine that had never had Thunderbird installed - so it was definitely a clean install. Same symptoms, but they sync and don't sync different messages. How do I get someone to look into this?
Moving this to a different path.......
I recently moved from a Win 7 machine to a Win 10 machine. In setting up Thunderbird on the new machine, I decided to use IMAP instead of the POP3 I was using on the old machine.
Thunderbird auto-setup wants to use the server mobile.charter.net, which is the same server recommended by a Spectrum spokesman. However, with an @WI.rr.com email address, mobile.charter.net does not recognize me and I can't log on to that email server. For many years, I have been using mail.twc.com, and that server still allows me to log on. However, I suspect that legacy server is not being maintained properly, and it is creating a problem for me trying to use IMAP. (Thunderbird is not recognizing all new messages)
How would I go about getting my credentials recognized by mobile.spectrum.net so that I could use that server? I DO NOT WANT TO CHANGE EMAIL ADDRESSES. I've had this email address almost since the inception of TWC and changing it would be quite problematic.
Going on 4 days now and still no email via Thunderbird & Spectrum. Something changed and it wasn't Thunderbird. I was using the TWC address before but tried the mobile.charter.net setting for both incoming and outgoing mail. My mail still will not download from your server and I still cannot write an email. This is the message I get.
An error occurred while sending mail: The mail server sent an incorrect greeting: p-impout001.msg.pkvw.co.charter.net cmsmtp 22.214.171.124 blocked AUP#CMBL.
So, Spectrum guy, can you decypher this error message and get me back running again?
Someone seems to have merged two threads here. My issue is Thunderbird not seeing all the new messages on the server. For example right now there are 19 new messages showing up on the webmail page, but Thunderbird has only loaded 15 of them. Trying to work the issue both here and on the Mozilla Thunderbird forums. TB works everywhere except mail.twc.com, and mail.twc.com seems good with other mail clients (Win10 'Mail' and 'Mail' on my phone). So it seems like a compatability issue. Both TB auto-setup and Spectrum support tell me to use the server "mobile.charter.net", but with the old wi.rr.com email address, that server does not recognize me. The only server that I can log into is mail.twc.com, and I suspect that one is not being maintained well anymore.