I like to manage email locally, so after Microsoft stopped supporting an automatic link between hotmail.com and Windows Live Mail, I set up an IMAP account to connect WLM with outlook.com.  This works well for receiving mail & it syncs everything just fine-- everything except sending.  I get an error alert every time it tries to send the messages from the Windows Live Mail Outbox.

Server Error:  3219.  Windows Live Mail Eror ID: 0x8DE00005

I have the IMAP account set up to require clear text authentication to receive & to send.  I have my Microsoft account set up for 2-step security, so whether or not I check the Account Properties SMTP security options box to log in with a password, it prompts me for a unique app password every time I open WLM, and sometimes it requires a password when I do a sync command.

I have already tried choosing different SMTP security options, and methodically recorded them.  One night, a few of my messages did go out after I retried checking a different box on the security options for sent msgs -- Amusingly, it was one night after I'd tried unsuccessfully to get help from Microsoft support.  The live person who came on after the virtual helper admitted he didn't have enough knowledge to help me, ended up simply giving me the link to the customer support starting place.

We do have slow DSL much of the day, but I'm experiencing this problem even when the internet is plenty fast enough.