Is your site suspended? If your site doesn’t violate the URL rules, it is most likely because it is HTTP or it doesn’t show in a frame.
If HTTP/HTTPS is the issue, it could be that you added a https tracker or rotator URL, but your original link in the tracker or rotator isn’t https
It could also be that website you are adding doesn’t work in frames (such as social media or Youtube links). You can test if your site has code that prevents it from being displayed here. Enter your URL and click ‘Check headers’. If a red text that mentions Header X-Frame-Options or no valid headers are found when you test your URL, it will not display in surf.
Sometimes sites that have been previously approved get suspended also. It may seem random, the script runs through all the sites now and then to check them for anything that could be a problem. This is done to ensure surfing is clean and smooth.
At times it will pick up on something (scripts, loops, redirects etc) and put the site in “Suspended” or “Pending approval” mode again.
For example, if a site is temporarily down or there is an issue with the server where it is hosted, it would go into “Suspended” mode. If this happens, it doesn’t mean your website isn’t allowed, just that there was a temporary problem. Just delete it and add it again.