I have today changed my BT Mail passwords. Having done this I can only receive mail NOT send. They sit in the Outbox!
I'm using a MacPro with El Capitan version software.
I have a vey urgent email to go. Can some one help please?
A warm welcome to Mac-Forums.
By coincidence, I also changed my BT password (PW) and questions and all the rest, today.
Changing your PW at BT level is one thing. Then you've got to change the PW at Mac Mail level. I am not being sarcastic, I promise. I had similar problems.
Go into Mail > Preferences (shortcut is Cmd + comma) > Click on your BT account.
At the bottom of the list is "Outgoing Mail Server (SMTP)". Look at what is listed. In my case it says "Btinternet". In any case, click on it and it will open a window including "Edit SMPT Server List". Click on that. Then Click on "Advanced". There's your Outgoing PW! Change it.
Please post back, success or otherwise.
Ian