I’ve asked a question earlier about worker is not being available from certain providers in the US: Worker is not available from certain providers in the US - #5 by denis.shchotkin
According to @mcorreia response, that was some DNS redirection/blocking by ISP.
After further investigation we found out that *.workers.dev domain is working perfectly for the same customers, but our custom domain - not. Does that mean that our domain was just banned by Comcast in certain regions (sounds really weird as we only have one small app on that domain). Or there could be some DNS issues on our end?
Our domain is on Cloudflare as well and we don’t have any other records except on pointing the domain to the worker (root domain). Probably I need to add some other records? Probably having one single record (I see it as Worker, but I guess it’s CNAME record) looks suspicious for ISP?