SMTP issues today iCloud with .mac/.me email???

Strangest thing today, my iPhone has been intermittently refusing to send emails from my .mac (.me) email address.

Getting the "does not allow relaying" error message and dumped into Outbox. After a period ranging from 20 mins to an hour, I hear the "whoosh" and out they go. At first shutting down my laptop gave the perception of fixing this (sync issue?) but no longer the case. My Apple email is again constipated.

SMTP settings all checked and correct and wouldn't explain why it goes down and then works again without doing anything.

Any other similar exps? Are they fiddling with something that's causing this?

Found random fix - not sure how permanent though.

Changed SMTP settings to smtp.me.com instead of .mac suffix I've always had. No idea why that's worked but touch wood so far so good - emails fly out instead of errors and outbox default.