Rasmerk stores the backup in the App Data folder of the Google account used when the backup was created. If you sign in with a different account on the new device, the backup is not found.
Fix: Sign in with the exact same Google account that was used on the old device.
Verify that a backup was successfully created before the old device was wiped. Backup requires Premium — if you were not on Premium at the time, no backup was made.
Rasmerk keeps the most recent backup. If the backup was overwritten or the Drive App Data was cleared, it may not be recoverable.