A fix has been implemented and now we're monitoring to see if this eliminates the 403 errors on custom domains.
Posted Dec 27, 2020 - 18:18 EST
Update
Users are still experiencing issues with custom domains resolving, which we are still investigating and apologize for the inconvenience. Projects do work at their glitch.me domain.
Posted Dec 26, 2020 - 19:20 EST
Investigating
We are currently investigating an issue where custom domains are returning 403 errors. Projects are still working at their glitch.me domains.