esp32 doesn't connect to wifi anymore

[robademar]

I'm using esp32 development card with Arduino ide and Blynk library. The sketch is reading 2 sensors and write the values to a blynk device. It was working
I was testing my code for reliability and it suddenly did not connect to wifi anymore. I loaded some example sketch and they also did not connect to the network. I then replaced the board and with a new one it worked again.

So it is quite clear that the board doesn't work properly anymore.
Now my question is :
is there any way to test it or reloading the microcode (that I've never tried) could restore the board?

many thanks