Failed to backup. The cache identifier does not exist

I am having an error with an Azure database backup routine.
All are successful except one.
The error is the following:

Failed to backup “DATABASE_NAME” database with “Full” backup type: The cache identifier C:\Windows\system32\dbo does not exist.

Making a backup in bacpac file from sql server with the same connection user is done without errors.
I would like to know the minimum permissions of the connection user to the azure database server.
Why is it necessary to access the master database to list all the server databases if the user and login were created in each database?

Hello Ignacio_Chertcoff,

To resolve the issue, please ensure that you have enough privileges for the list of databases and Read Only permissions for the entire database (for backup).

For a restore process, you have to have permission to create a database and write all database objects.

If you have any other questions, please let us know.

Thank you!