I have 2 gmail accounts configured under “Mail” and over the last few days 1 of my accounts when sending a new email shows the “smtp.gmail.com:xxxxx” as “Offline”, if I forced a send from it, I would have to type my password in again. Then it would send, but go back offline.
Even when re-setting the password under the Mail Account Prefs, no difference.
Here’s what worked for me.
1. Start a new message
2. Pull down the “smtp.gmail.com: xxxx” menu and select “EDIT smtp server list”
3. Click on the account that’s going “Offline”, select “Advanced”
4. Fill in the password and close.
I don’t know why, but the account that was having issues did NOT have my password saved (even though it was “saved” under the normal account preferences area).
All seems well again, even after closing and opening mail etc.
The very strange thing is, the “EDIT smtp server list” seems to be a sub-menu under the normal Account preferences, that can’t be accessed except the above way. Odd.
Hope this helps.