Mail account offline on MacBook Air and iPhone SE

On my MacBook Air and my iPhone SE I cannot send mail tho I can receive it. When I go to Settings/Account Information it shows the account is "Enabled" but "Offline". Clicking on that red "Offline" button does nothing. How can I get online?

It shows dots to hide the PW for IMAP and SMTP. I don't know what the PW's are. There are a different number of characters in the PW for IMAP and SMTP.