I am not sure about the errors message. I have a number of clients who all say they are unable to connect to Yorkshire bank feed.
I have seen there has been an issue in the past with this so was just wondering if this has been resolved.
Currently, Yorkshire bank is not on the new open banking, this may be why your clients are getting error messages, in the meantime, they will have to just csv the transaction in until there is an available feed on the new open banking. This should be coming out in the next couple of months.