Z endstop problem  

Z endstop problem

Some days ago, I bought a prusa, completely assembled, at first I had to do the xyz calibration because it marked me that it was not correctly calibrated when I printed (which I found strange, since the printers are already calibrated) , After the calibration and the selftest (in which everything is working correctly) everything works perfectly for 3 small prints, then when I try to print again, I set error with the level of the bed, turn it off and on, the message appeared The printer was not calibrated, so I used selftest to see that everything was correct, but, it marked error (endstops-wiring error z), look in the forum and apparently the problem corresponded to PANDA, that is connected in the Area of ​​endstops z in the rambo, verify that it was well connected, and I test to see that it works well, (in the support told me to put a metal material down and I Check if it turned on and off the light, worked correctly, it seems that the PANDAS has no problems).

When I tried to do the selftest, I said that there was an error and later the message (Static Memory has been Overwritten), so, I check the firmware versions, apparently the latest firmware version 3.0.12, fixed related functions With this message, to differentiate real problems. I update to this version, and the message disappeared, but the message of (endstops-wiring error z) continues.

When I do the xyz calibration it stays up, and it does not go down to the bed level, if I try a second time, it goes down to the bed level, it does the first 3 points (3 of 4) and in the fourth it does not seem to detect Nothing, continue with the next 9, and in the end marks error. I include the links of the error videos.

Video 1: I show the problem when trying to do the calibration and later when doing the selftest

https://1drv.ms/v/s!AvQSiygW3f23pDveB2RngaIeAva9

Video 2: I show the pandas, when doing the test that you told me to see if it works correctly.

https://1drv.ms/v/s!AvQSiygW3f23pDwQSgOORE52vGuA

Does anyone know what the problem might be?

Thank you.