Airplane VTOL dances left to right in one amplitude, pls help

VTOL two front motors installed
to servo. Airplane dances left to right in one amplitude. What could be the reason?
video

That’s 100% your yaw PIDS. Look at the wiki on tuning the quad copter mode of your VTOL and you’ll nail it. Be sure to start with the default values and go from there, but it’s definitely your PIDs.