Let me get this you have 7 mail accounts with TWC. and one of those accounts has 8 additional identities for a total of 15.

Perhaps you might like to share the actual error you are seeing. So far all you have said is you can not send mail

The troubleshooting information ends about the same time as the information it contains might get interesting. Primary cause of formatting issues like you describe are themes and add-ons, but you did not post that part of the troubleshooting information.

Restart Thunderbird with add-ons disabled (Thunderbird Safe Mode). On the Help menu, click on "Restart with Add-ons Disabled". If Thunderbird works like normal, there is an Add-on or Theme interfering with normal operations. You will need to re-enable add-ons one at a time until you locate the offender.

I notice that the incoming port for accounts 8 & 17 (POP) is 995, but all the other twc POP accounts use port 993, which is normally reserved for IMAP accounts. Perhaps some account cleanup would be useful.

Note, as mentioned, I am now running Thunderbird 60.2.1

Matt:

I have 7 twc accounts--I'm one person and would be fine setting these up as 6 identities under 1 primary acct., but they all have different passwords. The excess (15) may have occurred when, after speaking with the provider's tech support on the phone, I tried to change settings from POP3 to IMAP (which first worked, and now it's not IMAP).

The error msg. I receive when trying to send via startmail acct.: "Login to server smtp.startmail.com... failed." Have discussed at length w. startmail tech support, who said that my settings were correct.

Upon starting Thunderbird (and it downloading new messages), I get: "An error occurred with the POP3 mail server. Mail server mail.twc.com responded" ... This must relate to the fact that I was trying to change from POP3 to IMAP. Nevertheless, TWC messages do get downloaded.

Furthermore, today, trying to send w. TWC account--it appears to still be fine (message is in my "sent" folder), but then (for the first time) I received this error msg.: "An error occurred while sending mail: Outgoing server (SMTP) error. The server responded: Service not available, closing transmission channel."

I have no themes or add-ons / extensions ever configured. Nevertheless, per your recommendation, I have restarted Thunderbird w. add-ons disabled and re-started in Safe Mode. Result: Same issue and error message when I tried to send an email via my startmail account.

You said, "The troubleshooting information ends about the same time as the information it contains might get interesting." I'm not a techie, was trying to abbreviate the long page of troubleshooting info... What add'l parts do you think I need to share for your assistnace?

Restarted Thunderbird in regular mode, but sending prob remains the same...

sfhowes:

Heretofore (since prob started), I was unable to even see the window "Account Settings" other than a tiny non-functional window. Today, in SAFE mode (haven't yet checked in regular mode), I finally see Account Settings pages, and I have changed TWC ports to 995. Startmail account remains 993, per instructions from server, 'tho it is IMAP.

I want to "clean up" to have 7 TWC IMAP accounts (or 1 with 6 identities, but TWC accts. have separate passwords) and 1 Startmail IMAP account. Until today, in safe mode, I wasn't able to see Account Settings.

Now, in Outgoing Server (SMTP) Settings, I see 7 TWC accounts (port 587), then 1 Startmail acct. (port 587) -- I don't know what should be my "default," so I've made this the default now -- and then 3 TWC accounts (port 587). Indeed, I finally saw some leftover defunct accounts for an entirely different server (Earthlink) such that I was finally able to delete them. Re extra TWC accounts, I don't know which are safe to delete--perhaps the last 3?

I would advise you to set up each incoming account with a corresponding outgoing server that has the same user name and password. This will avoid the possibility that twc stamps outgoing messages with account X when messages are sent from account Y through smtp server X. Select an account in the left pane of Account Settings and check Outgoing Server (SMTP) in the lower right pane so that account X sends through smtp X.

sfhowes: Thank you much.

But I cannot see a functional "Account Settings" still. Only a small non-functional window (that reveals only one account--my primary twc one); nothing can be changed (except add or remove an account); nothing can be inputted. The only way I can even see settings is in Safe Mode, where I see Incoming: (pop3) mail.twc.com:995 SSL/TLS Normal password and Outgoing: mail.twc.com:587 STARTTLS Normal password ... plus Incoming; (imap) imap.startmail.com:993 SSL/TLS Normal password and Outgoing: smtp.startmail.com:587 STARTTLS Normal password. BTW, I don't know what "Default" refers to, but I have 7 twc accounts as "true" re default and the 1 startmail acct as "true" but 7 twc accounts as "false" [note: I don't wish to have but 7 twc accounts, total, and 1 startmail acct].

You suggest: "set up each incoming account with a corresponding outgoing server that has the same user name and password." Do you mean as it stands, above, *or* to have 1 twc account with the other 6 twc ones as identities without separate passwords? I would be happy to do the latter, but don't know how--perhaps need to call my twc ISP to ask.

In the meantime, since I can no longer adjust *any* account settings due to not seeing an operational window, how can I fix this? I have tried uninstalling Thunderbird (beta version) and reinstalling Thunderbird 60.2.1 *but* the problems remained, as my computer re-populated Thunderbird the same as 'twas prior to uninstall. I was expecting to have a clean slate without any email's, address book, etc. (which is inconvenient since only IMAP email's are backed up, but I accept this inconvenience), but perhaps I need to delete all Thunderbird files besides uninstalilng the program. I don't know how to safely do so, if this is what is needed. Again, my objective is to have Thunderbird with a functional Account Settings menu so that I can clean it up and make suggested simpler configurations.

Just to keep it relatively simple, I suggest leaving aside identities and instead set up the separate twc accounts. Also, don't bother with TB 63beta - stay on the 60.2.1 release.

Start TB in safe mode (hold Shift when you launch TB), and when the safe mode prompt appears, check 'Reset toolbars and controls' and click 'Make changes and restart'. See if that allows Account Settings to show correctly in normal mode.

The Default account is the one at the top of the left pane in Account Settings. The Default outgoing server is indicated when you select Outgoing Server (SMTP) in Account Settings at the bottom of the left pane.

Yay! Thank you--I didn't know to check "Reset toolbars and controls" while in Safe Mode... It worked--Now, as you expected, I can see Account Settings normally--phew!

In here, too, I could *see* and thus finally delete the correct 3 defunct accounts (leaving 7 + 1).

I *was* still unable to send ('tho I can receive) from my Startmail account -- i.e., one of my original issues. I, once again, deleted the account from Thunderbird and re-set it up with the configuration given by Startmail, but the *cannot send* (using Startmail) prob remained *until* I realized that I hadn't entered a changed password in the SMTP setting. N-o-w, I've got it.

Thank you very much for all the help!