Hi. Had the problem this morning.. tried opening and closing Outlook. Still a 'can't find server' error. So ran in Safe Mode, and the message was sent OK.

The addins I have are the following:

Active Application Addins:
Microsoft Exchange Unified Messaging
Microsoft Office Sharepoint Server colleague import addin
Microsoft Outlook Mobile service
NatSpeak OUtlook Addin (will be from Dragon Naturally Speaking)
SMime addin
Windows Search email indexer

Have Googled these and seem not to need most for home use, so have disabled addins that seem to be optional (most apart from the NatSpeak one) and will see what happens....

Thanks,

M.