POP account receives but doesn't send

POP account receives flawlessly but when I try to send a message, it says “no account.” (I have no problem sending w/ other mail clients.)
When I click “no account” it says “There is no account set up…”
When I run Diagnostic, it says “Ok” and gives a check mark.

Would greatly appreciate any ideas about what I’m doing wrong.

Thanks!

Go to Menu > Accounts and click on the General tab for this account. It needs to have both a POP3 (receive) and SMTP (send) service. If the SMTP service is unticked, just enable it and click on Save & Close.

If there is no SMTP service, you will need to setup the account again. When that is done, move all the messages from the old POP3 account folders to the new ones, then remove the old account.

Thank you so much! Your second paragraph solved my problem.