'A specified parameter was not correct: VM Group Missing'
Take a fresh file-based backup and an offline snapshot of vCenter Server Appliance (VCSA) Snapshot Best practices for vCenter Server Virtual Machines
Upload Logs: Please collect and upload vCenter support bundle to your support case Collecting diagnostic information for VMware vCenter Server
Uploading files to cases on the Broadcom Support Portal
The resolution requires direct modification of the vCenter Server Database (VCDB), it is recommended to seek assistance from Broadcom Support to ensure database integrity.