I am trying to tap into the 1" PVC main service line

So I installed the threaded compression tee. But the 1" main sprinkler pipe which connects to the outlet of the tee, keeps popping out of the compression tee when I turn the water back on.

I tightened with a pipe wrench to make sure the sprinkler pipe is secured but it still keeps slippig out.

Is it because the sprinkler shutoff valve is too close to the service line? I tapped in by going vertically about 6" and horizontally about 10" with the shutoff valve at the end.

I'm not sure what to do. Maybe I should use a "slip" compression tee where the sprinkler pipe is glued into the compression tee. But then I couldn't find those at Home Depot or Lowes.

Or is there too much pressure and it needs to be reduced?

Does anyone have a solution or any advice. Thanks so much.

Pochi