Two networks one for local streaming and one for internet

[LuMa03]

My fiber broke and i am now using a mobile router connected to the pc for internet but i want to stream with plex to my chromecast Ultra while using the internet on my pc. If i disconnect the mobile router and only use the ethernet cabel to the chromecast it works but if i connect the mobile router (while the ethernet is still plugged in) it doesn't work. I tried making a bridged connection (I didn't change any properties) it still doesn't work to stream locally but i can use the internet.

 

English isn't my first language so it might be poorly worded so just ask any questions if you need any more information.

 

Going to sleep now so won't be able to respond for a while.