Hi Trish.
I had a similar problem when trying to book European Rail Travel with SNCF, while holidaying in Europe. My Visa was protected by 'Verified by VISA', my bank in Australia could see my transaction requests (and approved them), yet SNCF kept rejecting my transactions 'because of fraud'. It turned out that I needed a billing address IN the country from which I was making the transaction, for the problem to go away. I asked my Australian Bank to change my billing address to our base address in the UK, and suddeenly I could book SNCF tickets from the UK (but not from France or Germany). Incredibly frustrating as many other online vendors did not have this problem. (e.g. eBay, and the UK company TrainLine happily allowed online transactions from several European places).
The British Office of SNCF wouldn't accept my solution and were not prepared to look further into the problem because of 'privacy' issues, so I made perhaps a dozen phone calls from France and the UK to SNCF and my Auusie bank. The main issue, in payment policies at SNCF, was never resolved. (It may well be to do with UK banking laws). Instead of booking tickets online, 'on the fly', I had to either return to the UK, or find a local railway station where I could 'sign' the credit card transaction. Good Luck sorting your problem out! Finding a 'techie' somewhere inside the bank or AirBnB who can REALLY identify the cause of the problem seems impossible.