You get a 96 when the conditions of requesting a tape cannot be fulfilled.
So what you need to look at.
Wrong media type.
If your tape drives are of type HCART you must have available media of type HCART for it to use.
If all the available tapes are HCART 3 then you do not have a match and it will give you a 96.
So check your drive type against the media type and see if they match.
You do not have a real scratch pool.
Look at the properties of your scratch pool and see if it is check as being one. Just calling it SCRATCH does not make it a scratch pool.
Check your policy for what storage unit it wants to use.
Is that storage unit configured to use the library that has the scratch tapes.