Clean Fail

[Luoni]

We're having a problem with our Tape Drive HP SureStore DAT24x6 external autoloader C1559B. It has been working perfectly until last week, where I noticed the message CLEAN FAIL on the display and the orange bottom light blinking. The backups still seam to be executed correctly, just the cleaning fails. I inserted a complete new set of tapes C5708A as well as a new cleaning tape C5709A, but the same error message appears again any time the cleaning tape is loaded (and disappears after ejecting/re-inserting the tapes). The local support advised me to mount the cleaning tape several times in a row. I did that but it didn't fix the problem.He then proposed me to install the L&TT tool which I did. I updated the firmware and launched the tests, it didn't detect any problem though. I would be grateful for any help on how to solve this CLEAN FAIL problem. Thanks in advance.