Hi,
I had the same problem as described at the beginning.
Edit my local GPO settings have solved the problem for me.
In Unraid 6.11 NTLMv1 was disabled, in connection with the new Linux kernel. But this was still stored as default authentication in the local GPOs of my computer.
Open your local GPOs and Find "Network Security: LAN Manager authentication level", which is located in Security Settings, Local Policies, Security Options.
I have set it to "Send NTLMv2 response only"
Description to find the Setting: https://kb.iu.edu/d/atcb
Level Overview by Microsoft: https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-R2-and-2012/jj852207(v=ws.11)?redirectedfrom=MSDN