Hi

I have a booking a few months off from ABZ-LHR-MUC return and I am unable to change my seats for any of the flights.

Every time I try I get the following error message

Error
Sorry, we are unable to confirm your seat request(s) at this time. Please try again later or check in at the earliest opportunity in order to choose the best available seat(s)

Anybody have any ideas why?

It is an award ticket but I have in the past been able to change seats for award flights

All my other bookings are ok