Change seat assignment doesnt work

This is second time this has happened to us. My wife and I are traveling together. Virgin assigned us separate seats a long way from each other. The app gives you the option to change seats, but doesnt work. After trying to change seats you get an error message. Calling Virgin Atlantic or checking the website is also useless. You have to hope the checkin clerk at the airport can do something.

Alec Style about Virgin Atlantic, v2.8.1