https://www.computerbild.de/artikel/cb-News-Streaming-Rokkr-App-Streaming-Roku-29029391.html

Because Rokkr uses proxy lists, your ISP can see you connecting to a known proxy server. Many ISPs now automatically block these ports. To fix this:

This is significantly harder than it sounds and requires daily maintenance. For 99% of users, sticking to community lists is the best approach.

The process is relatively straightforward, though it varies slightly depending on whether you are using the Android app, the Windows version, or a Smart TV variant.