An attempt has been made to service a mount request, but the attempt fails because the media type of the cartridge being mounted is not compatible with the devclass requesting the mount. This is usually a conflict between WORM and Read-Write characteristics.
The operation fails.
If this is not a 3592 device or media, The volume was probably not checked in with the CHECKLABEL=YES parameter of the CHECKIN command. Check the volume out (the REMOVE=NO may be useful) and check the volume back into the library with this parameter to ensure that the mediatype is determined and saved. If this is a 3592 device or media, the volume probably has an incorrect barcode label indicating that it had the wrong WORM property. The label needs to be swapped for the opposite WORM type (e.g. WORM to non-WORM or non-WORM to WORM) or simply removed entirely from the library.