Moto G6 plus "There has been an error with your request."

When I try to unlock the bootloader and enter the data string on the Motorola website, it seems to find the string ok, but when I tick the legal agreement and ‘request unlock key’ I get the message:

There has been an error with your request

This happens in all browsers I’ve tried. If anyone has any tips on how to resolve this issues, I’d love to hear them!

Regain your privacy! Adopt /e/ the unGoogled mobile OS and online servicesphone

Update: clearing my browser’s cache for the motorola site fixed the issue (in Firefox: history - right-click on Motorola site - ‘forget about this site’). I wonder if that could be because I recently unlocked a G7 phone on the same computer.