Symptoms:

   Invalid settings for VM Disk x:x    

Cause:

   Reflection issue between vCenter and Zerto Database    

Solution:

STEPS 
1. Log into the Source ZVM VM.
2. Run the "Reconfigure" option from the Zerto Virtual Manger (ZVM VM -> run the Zerto Diagnostic Tool -> Reconfigure Zerto Virtual replication)
3. Retry creating VPG

*If reconfiguration does not resolve the issue, please open a AssureStor support ticket.