Macbook Pro "cannot connect to Apple TV" (but other devices can)

[OSXphoto]

Hi guys, peculiar issue. My Late 2013 rMBP 15" won't connect to our Apple TV 4K all of a sudden. Here is what troubleshooting I managed to do:

- This particular 2013 MBP has worked flawlessly with this Apple TV 4K for over 2 years
- All devices on secure LAN on VLAN100
- Apple TV 4K over cabled ethernet connection: 192.168.100.91
- 2013 MacBook Pro 15" on WiFi (192.168.100.73) - no connection
- 2013 MacBook Pro 15" cabled ethernet (192.168.100.69) - no connection
- 2017 MacBook Air 13" on WiFi - success
- iPhone 11 - success
- InFuse app on Apple TV - success
- restarted 2013 MBP - still no dice
- restarted Apple TV 4K too - still nothing

After al this troubleshooting me + wife + kids watched an entire movie through the InFuse app which went without a glitch.

Any thoughts on what to try next?

Appreciate it!

 

[OSXphoto]

I found the solution! Apparently the firewall had been enabled in Settings -> Security and Firewall -> Firewall. After disabling it I could access the Apple TV again.