Powering an ESP32 board from external source issue

[mforbiz]

If I connect my ESP32 board to my PC via USB and upload any code via the Arduino IDE, all works fine.

Even if I disconnect the USB cable, when I reconnect it, the ESP32 board restarts and works perfectly.

If I disconnect the USB cable and power the ESP32 board by means a reliable power source (https://www.tek.com/en/products/keithle ... 231-series) either from Vin (5V) or 3.3 V, the ESP32 board doesn't work in any way even although the onboard LED is ON.
I've tried with many Arduino IDE codes and also with very simple code like what that blink a LED on/off I've the the same result: if the ESP32 board is powered from PC by USB cable, all works fine, if I disconnect the USB cable and power the ESP32 either from Vin (5V) or 3,3 V, the code stops working.
Any idea?
Thanks in advance.

[ESP_Sprite]

What board specifically are you talking about? Does the board start working after you manually reset it? (If the board does not have a button, touch a wire between EN and ground)