If this just happened, and you haven't made any changes to your setup since you were last able to synch : restart.
Then try to synch again. Save any work first of course. When you do try to synch again, click the details button and if it still fails, let us know what it said.
"Synchronization failed - Bad response from server"
Details button revelas this:
Start banner synchronization.
Banner synchronized.
Comparing local and online counters.
Number of successful auction uploads: 0.
Synchronization failed - Bad response from server
As before, I try again and a window pops up that reads:
"Invalid Auctionwatch UserId/Password"
I've checked to make sure my User ID and Password are correctly entered. Still no joy.