QUOTE (ohrenkino @ Aug 14 2012, 20:32)

If you have a firewall it could be that you have blocked mp3tag - this may also happen if mp3tag asks for an update.
Check the firewall blacklist and/or restart the computer.
Thans for the suggestion. The app works with Discogs and other features that use the net but just give error 400 with Amazon.
I did what you said and restarted the PC but it still gives an Error 400 when I try Amazon options.
When the error window comes up is shows"
http://webservices.amazon.com/ "
error 400. When I try and connect to that page through a browser it won't work either.
Any other ideas?
AFAIK, I never changed anything, it just started giving the error.