My WD My Passport Ultra is not recognised by my Blu-ray Player

WD External Drives WD Portable Drives
2

Check the partition type on the Passport and see if it’s GPT or MBR. I’d imagine your BD Player definitely supports MBR, but if the Passport is GPT, it might not support it.

If that’s the case, you should be able to format the Passport using an MBR partition.