You need to whitelist the domain if it is being blocked. It is also possible that the tunnel you are using is applying their filters to the tunnel.
You need to find all the domains accessed by that website/service and whitelist them all. Also try changing your tunnel IP on the tunnel page -> switch IP for all tunnels
One thing that will help is install NoScript, while using NoScript you will see domains you can also whitelist in DPR. Just don't whitelist any ad/tracking unless you want to defeat the purpose of the DPR unit.
Sometimes I even resort to scanning the source code of the website I am viewing (right click -> view source) and looking for hyperlinks - they will be actual links you can click to test if the resource loads or not. Then you whitelist the things you think you need. You can also use the Inspect / Dev console to see what resources are coming from where (under network tab) and then whitelist those depending on what it is. This is more technical and will require some technical knowledge.
