Outgoing hotmail stuck in outbox

Wondering if there’s any reason why hotmail might be sticking in the Outbox?
Incoming mail has no problems. It’s just sending out with eM Client is not working.
Phone and pad hotmail (not using eM Client) is working perfectly.

Same here. Outlook places sent item in “outbox” folder, and does not send. It’s working fine using other clients/web and incoming mail and other sync actions (deletes/moves) works fine. Started today.