After all the steps you went through without success, how about creating a small mission just brand new. Then run the mission. This is just an idea. But worth a try
I watched your track: The first time you contact JTAC, he answered but you did not go on at all. The second contact to JTAC, you were much to fast with your answer. Give it a 2-3 second break before it. I did the same mistake month ago and found out, I had to have this small break.
And I fiew Shooting Gallery without any problem. JTAC act the way he should. NOW, no more ideas.