Make sure all the fans are clean. Make sure the projector is not mounted too close to the cieling. This may block vents in the housing.
If you have to, you may need to mount a small fan near the projector to blow into the vents. Make sure it blows in the right direction. You don't want it working against the fans inside the projector.
Just for a test, unmount the projector and run it on a table. This should tell you if the mount on the ceiling is causing the problem.
Answers & Comments
It is most likely getting too hot.
Make sure all the fans are clean. Make sure the projector is not mounted too close to the cieling. This may block vents in the housing.
If you have to, you may need to mount a small fan near the projector to blow into the vents. Make sure it blows in the right direction. You don't want it working against the fans inside the projector.
Just for a test, unmount the projector and run it on a table. This should tell you if the mount on the ceiling is causing the problem.