In case the Avira Exchange Security - Small Business Edition doesn't update anymore since December 02, 2020 please perform the following steps.
- Open the windows service manager (WIN+R → "services.msc").
- Stop all Avira Exchange Security services.
- Open the folder: C:\Program Files\Avira\Exchange Security SBE\Bin\Savapi2
- Replace the file savapi2.key with the one attached.
- Start the Avira Exchange Security services again.