Rent now problem

Hi, We have a prospective tenant who is trying to put down holding deposit. They get to the payment stage and it keeps crashing. They have now attempted this several times from mobile phone, does this need to be done on laptop/desk top? has anyone else encountered this? any solution or advice appreciated.
Thankyou

Never had a similar problem, but could be problem with their phone/browser, so worth them trying an alternative. Depends where its crashing. it is trying to verify banking info via link to their banking app? are they using a correct UK based card?

they fill out everything and when it goes to confirm bank details it crashes

Sorry never happened to me. Perhaps ask the tenant to take screenshots and send them to openrent for advice