SMB 'Operation not permitted' after changing OMV network drive

I’m getting an ‘operation not permitted’ error when I try to connect to my network drive over SMB (from OSMC running on a pi 3b+). I have a budget NAS set up with OMV and a raspberry pi, which had previously been working fine. I recently upgraded my hard drive and reinstalled OMV. The IP address of the NAS is the same, and I created a share folder with the same name and password as before. However, now when I try to access the drive I get the error. The error also appears if I try to access it through adding a new network location.

The drive and share are working as I can access it through my computer.

Any thoughts on what could be happening and how to fix it?

There is actual an issue with SMBv2 and read chunk size, see SMB connection issue after June update - #40 by JimKnopf.

A fix of the issue in this article will be available, soon (or you can test it like mentioned in the article using the development staging).
If you could set your OMV NAS to use SMB3 as maximum version and set the mediacenter accordingly, this would be the best solution also regarding performance.
Another temporary trick till this fix will appear for all, could be to reduce the mediacenter max. SMB version to SMB1 for a short while.

Thanks, reducing SMB version 1 worked. It is strange that it was working before with SMBv3

SMBv3 should not have been impacted by the change.
I suggest to set both server/client to min/max SMBv3, should work.