Your android headunit has been running perfectly for a couple of months and then suddenly, it’s not working. There is a black screen, no display, but it was working just now.
Check for power
Every android headunit needs power. The 12v system powers the head unit. You need to check for a 12v supply being present at the headunit loom and the GND or earth also being present to make a circuit.
Fuses protect the 12v circuits and there can be several fuses involved in the supply to the android headunit. Checking for 12v at the head unit plug is a fast way to check all those fuses in one test. If you have a 12v supply at the power pin of the headunit then your fuses are good.
No power at the rear of the headunit or on the can bus box can indicate a blown fuse. You would need to change the fuse and see if it blows again. If the replacement fuse also blows, then check for a trapped or chafed supply cable.
All tests passed, black screen
If your power checks are passed, you get a good 12v supply to the power plug, look for the CAN BUS BOX, if there is one. The can bus box can control the on/off of the android headunit, so try a replacement can bus box if you suspect this could be faulty.
If you have power to the headunit and there is no can bus box, then you could well have one of the many non working android head units. They follow a familiar pattern: working perfectly one moment then just not working, a black screen. No sound, no picture is bad motherboard.
Magic Reset Button (RST)
You can try pressing the reset (RST) button if you can find it. This will powercycle the headunit. You have quite probably tried unplugging the power connector from the headunit while testing for the 12v supplies being present, but pressing that tiny button with the end of a SIM eject tool just one more time can help you fell that you have tried everything.
The android headunits are not unknown to fail very quickly and although some manage to struggle on for years, quite a few only make it to 18 months or so. The cost of repair can out strip the cost of replacement and after 18 months the technology has moved on anyway. This could be a good excuse to replace it with a later model. Just as you would with a phone.