No deflection in voltage regulator but the circuit works fine
You have a voltage stabilizer, it tries to maintain a stable line voltage going to the connected item. If you know the stabilizer unit worked earlier then it may be that you now have it wired incorrectly.
If the wiring is incorrect it may be possible you could damage the item being powered.  It is also possible that you could create a shock hazard, (especially if you cross a live wire connection with the ground wire).  Consult the user manual and carefully follow the connection instructions. If you don't have the manual or cannot follow the wiring then have a certified electrical contractor make the connections.
There would be a few incorrectly wired arrangements that may still allow the connected item to work normally. This might be the reason the meter is not working. But as I listed above there is a danger that some incorrect wire arrangements could be dangerous.