When you get it tight is there still threads showing on the sensor part? If so you could fix by............

It should have pipe thread on it which are tapered....... and the problem would be that the taper in the hole is less than the taper on the part...
You could fix this by getting a pipe tap the same size as the hole and just run it in alittle farther which will let you run the piece in farther...... FYI just do alittle at a time

Now if there is no threads showing on the sensor then you need a longer fitting

MM64