First, the default key is NOT Ctrl+Shift+F12, but it's CTRL+F12. This, of course, if you haven't changed it. You can check if you changed it, in the "Change key assignment" menu option of the "Couatl powered products" menu.
If you don't have services working, it's usually a result of a problem in your airport cache, or a problem in the AFCAD of the scenery.
To fix the airport cache, remove the folder C:\ProgramData\microsoft\fsx\SceneryIndexes
This will force a rebuild of the scenery cache both in FSX and then in GSX (you will see the red text saying the scenery cache is being rebuilt). After this try if it does work.
If is still not working, check for a corrupted .BGL file that might cause problems. To do this, enable Logging, open the Notepad and type the following on a new blank file:
logFile=couatl.log
(please note logFile is written beginning with a lower case l and a capital F )
Save the file as couatl.ini in the FSX\fsdreamteam\couatl folder, so it stays at the same level of the couatl.exe
Launch FSX, go to any airport, when it finished loading, select any operation (like Deboarding, for example), exit from FSX, check if you have a Couatl.log file in the fsdreamteam\Couatl folder, and post its content here.