Trying to register for crossclave

The first run I took to register for Crossclave in the SO-shop was with an instance of Firefox (v 87.0) under an Ubuntu (v 20.04). The result was a consistent and reproducible failure. (cf. so_cc_bug|349x216
I could complete the registration with a chromium browser.
However, I did not take the time to check out whether possible security restrictions of my browser might have been the cause.

I remember having seen the same error message. I finally managed to complete the process with Firefox, but do not remember exactly which script sources I had to enable in uMatrix to get it working.

We use Stripe for payment processing, and the Stripe js script needs to be able to run for the transaction to go through. That’s likely the culprit. I’ll do some testing on our end to see if I can get this documented so others will know exactly which script it is that needs to run.