Hey,
I've been using GSX with the Fenix for probably 6-7 years, have seen & worked through many of the issues.
Need more information though, using the Fenix as the reference ACFT:
1) Do you use simbrief to populate your flight plan into the EFB or are you manually inserting the data by hand into the w&b page in the EFB?
2) Are you attempting to start GSX services from within the Fenix EFB or are you using the GSX menu to initiate boarding?
3) is your custom aircraft cfg file loaded? (You can check from the GSX menu->customize Aircraft - with the Fenix, by default it should be using the developer supplied cfg, unless you did some manual configuration changes yourself.
4) if you are using simbrief, when you pull into a gate with a VDGS, does the OFP data for your flight (Route, Pax qty, SID/STAR, et al.) display on the VDGS after GSX opens and you have the green "simbrief ok" button?
5) if you start at a gate cold and dark, and open up the EFB and DO NOT import any simbrief data, but instead go straight to the W&B page in the EFB and manually add a random qty (within range obviously) of pax, cargo, and fuel and then click Load ACFT -->>Apply Instantly, if you then look inside the cabin are you seeing any seated passengers attached? (you should)
From your description it can be many different things, from as simple as a misconfiguration, the order of operations, or there might be a simconnect issue because your scenery+mod combination is making too many simconnect requests/connections which is causing GSX to hang. On the more dire side, it could also be a lack of CPU resources or physical memory which is causing couatl to hang.
if you are limited on your physical RAM, a good hack to free up more available memory prior to launching MSFS is to download the small free RAMMAP utility, and then prior to launching MSFS open the Task Manager, navigate to ->Performance Tab->Memory, and keep the window with the memory composition progress bar to the side for reference. Then launch RAMMap.exe, and from the drop-down menu click Empty->Then Empty all 4 buckets of memory in the menu (from top to bottom, Starting with "Working Sets"), while watching the memory resources tab you already have open in the Task Manager. (Do not empty the next category immediately, wait until you have noticed that the memory contents progress bar has stopped moving). This will put your system memory (including cached standby memory) in a clean state and purge any spurious memory not in active use by the system shell, kernel, or user space. It's safe, I have plenty of available system memory and I do this prior to any flight regardless, even if the PC was just restarted.
I Tried to keep this as simple as possible, let me know about 1-5 above and I will see if I can help you further.
