Error adding second backup disk

Hi

SBS 2011 standard.

I added first backup disk and it worked great. I disconnected first disk and connected a second new disk. Now when in Windows SBS Console (Advanced Mode) - > Backup when I use Add or remove backup destinations to select second disk I get below error in the Configuring server backup wizard;

Cannot configure backup schedule: The server cannot configure the backup schedule. Please try again.

How can I add the second disk to the backup please?

Thanks

Regards