'Incorrect greeting' happens when you have the wrong server or wrong settings. Try this for the outgoing server: mobile.charter.net on port 587, SSL/TLS security (not STARTTLS), normal password authentication, User name = email address.

https://support.mozilla.org/en-US/questions/1234783#answer-1157069

SF, does it matter that I'm on a desktop and not using a mobile device?

It shouldn't matter, but the settings I suggested have worked for other Charter/Spectrum users, and I don't recall them mentioning they were using mobile devices. According to Spectrum:

"These settings are required when setting up your email on a laptop or desktop computer, smartphone, PDA, tablet, eReader or other mobile device."

You may want to check your incoming settings, i.e. mobile.charter.net on port 993 for IMAP, SSL/TLS, normal password authentication, User name = email address.

First, thanks for your help so far!

OK, I set that as default, but I did not delete stmp.charter.net and still got the same error message. Then I deleted that and made the mobile.charter.net the default. It tried to send a test message, but got the following error message:

Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) mobile.charter.net timed out. Try again.

I did try again, with the same result. Any idea why this is happening?

My incoming messages are arriving fine, so I'm reluctant to mess with them, unless you feel it would affect the outgoing emails.

Do you have an antivirus program scanning outgoing mail? That is the usual cause of timeouts, especially with SSL connections, so you should disable email scanning if it's an option. Also, make sure your charter account is sending on mobile.charter.net and the gmail account is sending on the google smtp. You can check this by selecting an account in the left pane of Tools/Account Settings and looking at the Outgoing Server (SMTP) box in the lower right pane.

No need to adjust incoming settings at the moment, as long as the incoming account and the outgoing server use the same User name/password.

I don't believe I have an anti-virus program scanning OUTGOING mail, but before you suggested the settings you did, I'd had Security Connection set to "none." Just for the heck of it, I reset it just now to "none" again and tried to send an email - same result, connection timed out.

I looked at the Outgoing Server information; gmail is definitely going out on stmp.googlemail.com, and charter is set to go out on the default, which is now mobile.charter.net. I just looked to see if I could delete the default and just use mobile.charter.net without designating it as the default, and the delete button is inoperable when I highlight mobile.charter.net - I know that wasn't the case when I deleted stmp.charter.net, so not sure why I can't now delete it and remove its default status.

By now, I'm sure you're as frustrated as I am, but if you've got any ideas, I'm happy to try them! Thanks for hanging in there with me.

The connection security for the outgoing mobile.charter.net should be SSL/TLS on port 587. Change the security to SSL/TLS, which will automatically change the port to 465, then type in 587 for the port. Without the correct settings, there's no chance you'll be able to send.

You can't delete the Default smtp server; you have to set another server as Default, and then you can delete the other one. But in this case where you have each account sending on the corresponding smtp, it doesn't matter which is the Default. Default server only affects which account is invoked when you click a mailto link in another app, e.g. your browser.

Are you sure there's no AV program interfering? One way to test this is to start Windows in safe mode with networking and see if sending works properly.

Victory!!! Thanks, sfhowes, for hanging in there with me on this irritating problem - retyping the port did the trick.

RoseQueen said

Victory!!! Thanks, sfhowes, for hanging in there with me on this irritating problem - retyping the port did the trick.

What specifically did you do that fixed it? Thank you!

I'd already changed the outgoing server to mobile.charter.com, but hadn't changed the port number, which is why the server change didn't work for me. When I changed the port number from 465 to 587, that did the trick.

Hi - I'm experiencing this too. No settings were changed for years prior to this new error. I did all the suggestions above to no avail. Any other thoughts?

Thanks in advance