Since the upgrade to SP2, I keep getting this error, even though I get my email and can respond and compose and send. However, it is really annoying.

This problem can be caused by incorrect account settings. To adjust the account settings, follow these steps: Open Outlook.On the Tools menu, click Accounts.On the left side of the window, select your email account. In the Outgoing server box, enter the correct SMPT server information. Make sure that override the SMTP port is selected. Enter 587 in the box.Close the Window. And you can also refer to this post. Hope helps.Noya Lau TechNet Community Support

This problem can be caused by incorrect account settings. To adjust the account settings, follow these steps: Open Outlook.On the Tools menu, click Accounts.On the left side of the window, select your email account. In the Outgoing server box, enter the correct SMPT server information. Make sure that override the SMTP port is selected. Enter 587 in the box.Close the Window. And you can also refer to this post. Hope helps.Noya Lau TechNet Community Support

Just got back from vacation and saw this. Thank you, it worked as soon as I did your suggestion above and in "More Options..." button, I also had to put "Use Incoming Server toggle" Now have to figure out how to sync GoogleCalendar with the Outlook Calendar. Nothing seems to be working so far. Thanks again