This indeed seems like a strange issue. I am assuming you are protecting users? (Mailboxes / OneDrives...)
If so, please log a support call. Failed to obtain license seems like we have issues to determine whether your users in M365 have a valid Microsoft license.
It's an all in one installation so there shouldn't be any issues with connectivity between server and proxy. I recommended that they open a ticket as this is a production instance.
A couple of general comments for future revisions:
- the wording in the logs etc. is unclear about what kind of licence it's referring to at different stages. If future versions could state "Veeam licence" and "Microsoft licence" depending on the context that would eliminate some confusion
- it's unclear what the impact is for the various licenced/unlicenced states are on the backups