After updating to version 1.3.1, remote control is no longer possible.

[Schelli79]

Since the update, I can no longer connect to the client; the Connect button is not active.

[silversword411]

This isn't a problem with 1.3.1. if other agents are working that is an agent having mesh problems

https://docs.tacticalrmm.com/troubleshooting/#take-control-or-remote-background-missing-button-cant-connect