If you're using Legacy DNS (UDP 53), ControlD must keep track of your IP address in order to enforce your profile. If your IP suddenly changes, and you're using a custom/premium resolver, it will stop working until ControlD learns about your new IP. The process to do this is simple: visit Contold.com (this domain will always work). If you're logged in already, you will get a message that a new IP has been learned.
If you're logged out, simply login into your account (and choose to remember the login to avoid this in the future). Everything should start working.
Some DNS services employ DDNS (dynamic DNS) to learn your IP address if it changes. With ControlD, you don't need to use those services. Simply configure DNS-Over-HTTPS (DoH) directly in the browser that you use on daily basis, on the same network. When using DoH, your source IP is irrelevant, and your custom resolver will always work. As a bonus, if you're using Legacy DNS on your router, or other devices on your network that don't support DoH, your IP will be updated automatically when you make queries against your DoH resolver in the browser. Everything will just work, and you don't need any 3rd party DDNS solution.