I used cryptsetup to perform the following function

cryptsetup -y --cipher aes-xts-plain --key-size 512 luksFormat /dev/sdb1

An error occured saying it couldnt be performed which i pretty much ignored
and just thought i won't bother.  I did note that it mentioned about kernel
compatability though.  The drive appears to be encrypted and wont accept
the passphrase set.  This has just under 1.5 tb of information i can't
afford to loose.  Do you have any solutions, i have looked online but am
absolutely stuck

Cheers

Si