I haven’t worked that much on azure, or other clouds, myself, so I can’t conclude how this snapshot thing works. but be careful about its type. there is a concept of “incremental snapshot” that just saves the difference between the last save and now, and it differs from a single-full backup. check what type is yours.
also, the running instances and data volumes might reside in different places. so you also need to be careful with them too. the service config file might also be in another place. you need to check the cloud settings and make a mapping for these.
but overall, you will need to back up the data and config first, then work on the config file to fix the auth user problem.