Today, it stopped working again -.-

Today it's working again.

@metsam

There are some alternatives:
https://www.makeuseof.com/tag/cast-media-windows-chromecast/

But in my opinion only Videostream was the only good way to stream video media from PC to Chromecast.

In the meantime I will use an external SSD as my TV supports several codecs and drives. Hope they can fix it soon. Don't want to end up with a solution like building a NAS station.

@loconz
Hopefully not. I bought lifetime premium :D
I'm pretty sure they are working on a fix.