Solved Strange Connection Issue to File and Print server

I have a Windows 7 desktop serving as a file and printer server which has two external drives connected (from which we can connect to both laptops). We have a Windows 7 laptop which can access all three disks on the server, as well as the other laptop. We have a Windows 8.1 laptop that recently can only connect to one of the server's external drives, and neither the other external drive nor the internal one. Windows says it's a permission issue, "Windows cannot access \\server\folder
You do not have permission to access..."
I have rolled back several windows updates, which did not help. I have restored the Windows 8 laptop back to a time when no issue existed, which did not correct the issue. Has anyone had a weird situation such as this, or better, knows where I might look next.

Well, it appears that after resetting our router (TP-Link Archer A7), we're back to all access. But what is puzzling, is this issue was only happening with the Windows 8 laptop. Any ideas on this conundrum?