So looks like it’s trying to mount tape FA9585 but is unable to do so as the tape is already mounted (or stuck somewhere).
First thing you should do is disable that tape, so CTA stops trying to mount it.
Second, check the logs to see if there are other tapes in this state, or just this one.
Third, use the tape library GUI to find out where the tape is stuck so you can solve the problem.
Once you have unstuck the tape you can re-enable it.