It is possible that the linkage information on the X side could be expired (the access token could be expired).
We would appreciate it if you could log out of X, log in again, and then try to link your X account on the campaign site again. If this does not resolve the issue, please contact us using the button at the bottom of the page.
When contacting us, please copy and paste your ID listed at the bottom of the Pre-Registration Quest campaign site into the inquiry form.