First step to get your system up and working again is to simply turn everything off.
Sometimes the inverter may need to reset itself.
Turn it off and leave it for 5 minutes.
A PV system should have 2 isolators. (switches) A red one and a black one. The red is the AC isolator. This isolator is normally found by the inverter, it should been labelled. This is giving power to the inverter from the mains. The black isolator is the DC isolator which brings the current from the solar panels. This will have high voltages coming from the solar panels as long as there is daylight. Again, it should be labelled.
Do NOT open either isolator, simply turn them to the off position
Once all power is off there shouldn't be any power getting to the inverter from the mains or the solar panels. This will allow the inverter to have a rest and potentially reset itself. Don't worry, you won't lose any data on the inverter.
After a few minutes have passed turn the inverter back on and wait to see what happens.
If the probelm is still there, please fill in your details on the home screen and we will try to help out as best we can.