I upgraded a fully working v8 Veeam installation to v9 yesterday and now my tape library is marked as offline and nothing I do seems to make it online again.
No hardware changes were made yesterday, I didn't even enter the server room

I've restarted the Veeam server several times and tried rescanning the tape library but it's still offline. The rescan sits for a few seconds and then becomes "idle".
The only thing I haven't done yet is power cycle the tape library, but I won't be in the office until this afternoon so can't do this yet.
I've logged a support Case # 01747089.