GPT rejected -- may not be recoverable.

[KenwoodFox]

Im seeing this error on startup

Code:

GEOM: multipath/disk23: corrupt or invalid GPT detected.
GEOM: multipath/disk23: GPT rejected -- may not be recoverable.
GEOM: multipath/disk22: corrupt or invalid GPT detected.
GEOM: multipath/disk22: GPT rejected -- may not be recoverable.
GEOM: multipath/disk13: corrupt or invalid GPT detected.
GEOM: multipath/disk13: GPT rejected -- may not be recoverable.
GEOM: multipath/disk12: corrupt or invalid GPT detected.
GEOM: multipath/disk12: GPT rejected -- may not be recoverable.
GEOM: multipath/disk24: corrupt or invalid GPT detected.
GEOM: multipath/disk24: GPT rejected -- may not be recoverable.
GEOM: multipath/disk11: corrupt or invalid GPT detected.
GEOM: multipath/disk11: GPT rejected -- may not be recoverable.

and I am no longer able to import this pool.
I'm worried, as my last backup was over a week ago, my tape system has very recently failed, its awful luck these two things would fall together..
Can I rebuild the GPT or is this a sign of some other issue? What tests can I do? Some of these drives are very old but enough of them should be healthy SMART wise to recover the pool.
Thank you for reading.