I had a similar thing in 2018 when I rejoined Motability but it was with my driving license.
Nobody at Motability could tell me what the problem was but there was a problem but they would not tell me despite asking.
The dealer rang me a day or so later asking if I could ring DVLA to give Motability permission to get information about my driving license of which I did and everything was OK from there on.
What I did not understand is why did Motability not ring me instead of the dealer.
Must agree, you couldn’t make it up. ?♂️