AC Compressor not turning on

Hello guys. I noticed that my AC compressor doesn't turn on when I turn on the AC and the car just blows air. I cannot see any leaks under the bonnet (last summer Toyota dealer recharged the system the right way because it had lost some freon but it still blew kind of cold air) but I saw that the car is low on inverter coolant (below low mark). Why the compressor doesn't turn on and could it be because the car is low on inverter coolant? Please help I'm freaking out and here in Greece AC is a MUST.

 

Yes but the AC wasn't working from the morning when the car was all the way cold. Could it be because it detected the low coolant in the inverter and for a precaution it doesn't let the AC Compressor turn on?

 

Yes guys it might has leak I agree with you but why would the compressor NOT turn on?

 

Alright guys I checked the AC codes and 21 and 23 popped up. I know 21 is because the sensor doesn't sense light and 23 because there is no refrigerant in the compressor and because of the low pressure it shuts off so not to be damaged. Am I correct?
Also I took a look around I saw that the inverter pump works perfect and the hoses I can grab are totally dry but when I saw the undercarriage I saw that something is wet from coolant and it has dried on a few spots. Any guesses what could it be. I am uploading a photo.

 

The problem is that the coolant wasn't touched by anyone in at least 4 years (a year before Corona Virus to today). I will go to service shop to see the full undercarriage and make sure that nothing is dripping and I will make sure that it is tightened.
As for the AC I wrote the codes that the car showed and when I take it in for the coolant I will check the issue. I hope that it's just a leak and the compressor is fine.