We have our backups failing with errors 830, 96, 252, etc... Note that we are using Symantec Netbackup. I was not able to find the cause first thinking it was drives errors as our library was not serviced since years. Later my lead suspected beyond the drive errors then he found the hardware issue.
Gripper probably has a tape stuck in it. I have opened the door and turn the robot towards me so i can see if there are tapes inside and i have discovered a tape was stuck inside the gripper then there's a small mechanism on it, like a plastic rope that you can move with your finger. Pushing it back allows you to get the tape from the gripper. As after removing the tape from the gripper still it didn’t solve my issue then later the IBM engineer came down to our site and replaced the two grippers as they both went faulty. Now my backups are just running fine.
You can find the faulty Gripper in the below pics.