I can start PHD2 by connect equipment within PHD2, but not by the Connect Gear button in SGP 2.4.3.4 beta.
An error message is shown: “ASCOM driver problem during connection (ASCOM.Utilities) The PortName cannot be empty. Parameter name: PortName”
Moreover, I cannot start the looping in PHD2, it gave a timeout message. I can only restart the looping, after I click Disconnect all equipment in SGP, and reconnect the guiding camera within PHD2.
It seems like you might need to work out some issues on the PHD2 side before you start using SGPro to talk to it. From what you describe, it seems like your PHD2 profile is either in a bad state or PHD2 cannot connect to the device specified in the profile.
What guide camera are you using? Is it connected to the machine?