Perform the following actions:
1. Run regedit.exe and locate the HKEY_LOCAL_MACHINE\SOFTWARE\Veeam\Veeam Endpoint Backup key. Create the following value under this key:
Name = Recreatedatabase
Type = DWORD
Value = 1

2. Go to Control panel > Administrative Tools and run Services. Restart the Veeam Agent for Microsoft Windows service.

A new database instance will be created (this usually happens within 5 minutes).