V10 mail stuck in outbox

Since I updated from v9 to v10 outgoing mail (from hotmail accounts) is stuck in the outbox. All sends worked fine until immediately prior to the v10 update, then stopped working immediately after. So I did a complete uninstall of eM, followed by a new install. The problem remained but I guessed could be a teething bug to get a fix fairly soon. Still not working though. I can’t see any obvious fixes or others having similar problems. Any ideas please?

Thanks.