I run "bpmedialist -summary -brief " and email the output to myself everyday.
You can see output like this:
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MEDIA SUMMARY FOR SERVER GROUP All_Servers ON Tue Feb 11 11:19:05 2020
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ACTIVE FULL SUSPENDED FROZEN IMPORTED WORM BE_MEDIA ENCRYPTED
122 4004 6195 0 0 0 0 0
If you go to the GUI, Media and Device Management, and select Media, right click and filter for starts with "FRO" it will display your frozen tapes. Once you determine WHY they are frozen, you can right click and unfreeze them.