Did you find a solution for it? I am struck with the same problem and am not able to resolve it for days now.

If its zip or some issue with xlsx file then how could it work on a local drive.

So definitely some sort of permissions or access issue.

I too able to run xp_cmdshell dir on the network path and get the results but could not use ORS. (but ORS works on the same excel file if copied to local C: drive)

Really appreciate your comments as you have faced this problem before.