Gamertag processing error

Discus and support Gamertag processing error in XBoX on Mobile to solve the problem; I'm trying to change my son's gamertag and I've already added the funds to his account to do so. When I try to change the tag it says "we're having... Discussion in 'XBoX on Mobile' started by LRJK, Jun 29, 2020.

I'm trying to change my son's gamertag and I've already added the funds to his account to do so. When I try to change the tag it says "we're having trouble processing your payment and would like to get it sorted out". I've tried a number of times, all failed.
I've tried logging out completely, clearing cache and site data, trying different browsers, etc. Any ideas?

The error code is:

HjozhDL9layZrqiT/63blp.0.11

:)