Air lock happens when your jets stop working because of air in the plumbing pipes. In most case, it's relatively simple to remove. Take these steps:
Turning on priming mode
Turn the jets on low for 10 - 20 seconds
Turn the jets on high for 10 - 20 seconds
Repeat these steps 3 - 4 times if needed until everything runs smoothly.
If that doesn't work, check for leaks and clean the filter. Make sure the tub is fully filled. Don't try too hard; running the hot tub with air lock for too long can damage it. The right expert can take more advanced steps to fix the problem.