If your FitBit application requires running on port 8080, you will run into exactly the problem you have because MagicMirror also runs on that same port. You will have to change one of them. MagicMirror is easy to change, it’s in the config.js file. Change the port setting to something else, like 8081 …or 8585 … or 8123 … doesn’t matter, as long as it’s above 8000, and not 8080 since the Fitbit runs on that port.

@yawns I tried that one but can`t find the right install file to put it on…! I used the V59 version

An extreme measure here would be to try this: https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=41898&start=25 xscreensaver can be used right off the menu… you can set/turn on/turn off functions.