The error message you have indicated occurs because your PC blocks communication between programs. Add the programs you use to the exceptions of windows defender and antivirus. In general, I recommend that when you get to a configuration that works you do not run more updates, especially if you travel for do imaging (not your case i see dome setting up).
For Maxim Voyager it only sends commands … it does not directly control the camera nor download the images. You have to investigate something else.
Communications between Voyager and PHD2 doesn’t need mount connection. The test you wrote don’t help. “Busy error” mean protocol corruption or blocking from Defender or firewall. Using mount with POTH may cause a loose of a lot of ASCOM functionallity.
It does seem like a Windows 10 update this week has caused new problems with applications talking to each other. I have not yet seen with Voyager but have seen on two machines with other software. When I started TheSkyX it asked for my serial number like it was a new installation. Maxim DL said “could not initialize guider output.” Both were working fine before the update.
I am running Windows 10 home so you can’t turn off updates permanently. Probably worth the $100 to update to Professional and stop the madness!!! Third time in 6 months that a Window 10 update broke things with working programs.
I will see if adding these to the the antivirus / Windows firewall configuration helps. Just a heads up that there is a new Windows update that has caused some problems.
If you have win10 … disable Defender is an option to evaluate. Because window switch on Defender without ask to user.
“PHD2 is busy” is a courtesy error message from Voyager when a command from Voyager was not executed by PHD2 and go in timeout. This mean Defender or antivirus are blocking tcp-ip connection, inspecting packet in tcp-ip connection, guide camera is freezed , phd2 is freezed and if you not use ST4 (and i recommend to use it) and use mount … mount driver is blocked or phd2 freezed waiting mount driver. Voyager doesn’t need mount connected to PHD2 also a lot of mount driver doesn’t allow more than one connection.
If you add exception in defender for file, dir, process you are sure to prevent OS side problem with reasonable success.
Also you can postpone the update since to 180 days in win10, if you do update scheduled you could avoid this update problem. The best is to use previous OS for observatory PC.
POTH work because mantain ASCOM status , work without tcp-ip … but this mean PHD2 receive old data from the mount.