Computer can't find my roon core working earlier today

Roon Core Machine

Connected Audio Devices

I have chromecast attached but don’t use it with roon, there as a usb hard drive attached to the sonic transporter. everything as attached trough ethernet.

Number of Tracks in Library

16,000 tracks

Description of Issue

when I try to open roon it looks for the core but can’t find it. I’m not too tech savy but have tried rebooting the system and exchanging cables, I’m lost beyond that.