Have you tried the drive connected to any other devices to see if they will connect? If not, I would start there. That will give you a better idea on if the problem is coming from the tablet or the drive.
If it will connect to another device (say a computer) then I would start looking at the tablet. What changed? Updates to the OS? New apps installed? Apps updated?
Also check the tablet for malware, viruses, bad apps, etc.