Situation: The client has a problem to run Veeam backup with this error: “The user name or password is incorrect”
Resolution 1: Make sure use the correct username to access backup storage, for example NAS\username.
Resolution 2: The client just join the NAS to their domain, they need to access the NAS using domainname\username.
Resolution 3: Force the credentials renew in Veeam DB. Please follow this post: How to force the credentials renew in Veeam DB
Resolution 4: Run rescan on Repository by going to Backup Infrastructure.
Resolution 5: Remove the Backup reposition you don’t use it.