This problem has been going on for sev prob sev years.. I can see In box fine. Sometimes not Drafts/ What am I doing wrong? Or have I unchecked something please explain I have Sierra 10.12.6..... I Please explain Thanks all
Depending on your e-mail provider (Yahoo, Gmail, Outlook or others), you have to select the Drafts Mailbox and Sent Mailbox in Mailbox Behaviors preferences.
"Mail > Preferences, click Accounts, then click Mailbox Behaviors" https://support.apple.com/guide/mail/cpmlprefacctmbox/11.0/mac/10.13