I can't see Media Player

Hello!

I'm trying to see media player in Home Assistant, but unfortunately the HASS Agent's device of my PC is 'unavailable'.

The MQTT stuff works and I can transmit sensors data and send signals to PC just fine. It's just that the HASS Agent device appears to be 'unavailable'.

I already did a mild attempt of reinstalling HASS Agent on PC and HASS Integration in HA.

(I removed HASS Integration from custom_components, rebooted ha, installed it back, rebooted ha. For HASS Agent on PC, I uninstalled it and wiped it's appdata files and installed it back again)

TL;DR:
- MQTT works
- HASS Agent Device doesn't work - I don't have media player. It says 'unavailable'

All help is super appreciated - I'm a Home Assistant noob so I'm sorry if I didn't provide you with necessary logs, etc. - I simply don't know where to find them. But when I went to 'Settings' -> Logs, it didnt say anything useful.