I have been facing this problem with a couple of my key domains since yesterday.
Yesterday all of a sudden the DNS resolution stopped working for one of my websites which had been working perfectly for last 2 weeks. The domain was purchased from Godadddy. I waited for a couple of hours thinking that problem would go away on its own. But that didn’t happen. So, I removed the website from Cloudflare and went back to Godaddy the resolution still didn’t work. Wait for several hours still didn’t work. Tried to add it back to Cloudflare. It didn’t work. It kept waiting for name servers to be transferred.
Finally today I lost hope and purchased a similar sounding domain name from a different provider (Namecheap) and started using that. I added the domain to Cloudflare and modified name server in Namecheap. The site started working within a few minutes. Configured SSL/TLS etc everything was working. It worked fine for 4-5 hours and then again all of a sudden DNS stopped working.
It can’t be a problem on the domain provider side as the name server where already changed to Cloudflare. Also, the problem happened with two different domain providers. So, I am suspecting Cloudflare now. Are my domains getting black listed for some reason. I didn’t receive any email etc from Cloudflare or my domain provider. I am not using my domain for email etc. It is only being used for hosting a website. It is kind of becoming annoying. I am now going to purchase a new domain keep the show going. I am afraid that it might happen again with the new domain. I am using the free plan right now. Has anyone else ever experienced such an issue earlier? Appreciate any help in understanding and resolving the issue.