@Matic Kutnjak Welcome to Microsoft Q&A Forum, Thank you for posting your query here!
It seems you're encountering a issue with Azure Files permissions and mounting the share with a Storage Account key.
I would recommend you to contact support, so If you have a support plan, I request you file a support ticket, else please do let us know, It's better options for your scenario, It needs deeper investigation.
Please verify if the user has the right permissions to the access the resource:
Verify correct RBAC role on share.
Verify the user has correct NTFS permissions to the resource.
Verify the user has correct share permission to the resource.
Please go through this document for more details: Configure directory and file level permissions over SMB Also go through the Troubleshooting guide: Troubleshoot Azure Files problems in Windows (SMB)
Please let us know if you have any further queries. I’m happy to assist you further.
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