Emails using Thunderbird won't 'Send.'
Since October 18, 2023, emails using Thunderbird will not 'Send.' My nephew, who is very good at technology since that's his job, did change my Inbox to 'imap' from 'pop' as that's the direction my server, Spectrum (aka Charter) has gone, so I'm receiving messages. I"ve called Spectrum twice, but they haven't been able to help me, as their people aren't well versed in third-party servers. The 'Send' is still a problem, which he thinks is something going on between Thunderbird and Spectrum's server. Please advise. Thank you.
Try changing SMTP server to mobile.charter.net, port 587 and connection to STARTTLS and normal password. If that doesn't work, try changing STARTTLS to SSL/TLS. Report back on status. You are not the first to report that Spectrum does not provide tech support. Unfortunate for their users.
No, it does not solve the problem. I first tried the port 587, STARTTLS, and normal password option. Didn't work. Then I did the SSL/TLS, and it said it was copying the message to "SentMail" folder. "Not placed in SentMail folder due to network or file access errors." Each time, another message said it had 'timed out.' Said to save my message into Local Folders/Sent Mailemail@example.com (IMAP).
It appears to be a problem between Thunderbird and Spectrum Server.
I suggest you try disabling your antivirus and see if you still have these copy errors (they are not send errors. The message sent) you might also want to check on the spectrum web mail to see if there is a copy in the send folder.
Google at least add outgoing mail to the sent folder as it passes through, that in itself can cause issues on Google because the IMAP add and their own is concurrent. Perhaps this is what is happening with spectrum, in which case you can change Thunderbird setting so it does not save a copy of sent mail.