Storage is temporarily not available on SMB/CIFS external storage

We have a community 24.0.3 NC server (Ubuntu) that we use as private cloud to provide access to production folders on our Windows Server 2016 file server the folders are linked as SMB/CIFS external storage (Login credentials - Save in session) with LDAP/AD integration.

This works great for years but sometimes and only when a user try to upload multiple files at one time it receive the messages: “Storage is temporarily not available” / “Storage with mount ID is not available” and the upload stops.

Uploading one file at time the problem does not occurs.

How can I fix it?