WiFi LoRa 32 V3 external CC power (no battery)

I want to use a module as a web server not connected to a computer neither to a battery, but to an external power supply. I was confident a USB wall plug mobile charger tthrough USB-C would do the job, but that is not the case.
Some times the board starts up but it is not able to connect to WiFi, it remains trying to connect for indefinite time. Some other times it connects to the wifi properly but the server does not answer. Tried with a couple of different cables without any improvement. Only way to have it working properly is to power from a PC. Do you know why?
Should I want to use an external power supply should I use 5V or 3.3V? To which pin I have to wire the supply? I see 5V 3V3 and Ve pins on the pinout scheme but I don’t understand if they are power inputs or outputs (e.g. to power sensors etc…).
Thanks a lot.

USB power adapters should supply 5V with at least 1A, and should have USB-A type port. Then connecting USB-A to USB-C should always work as long as the cable isn’t faulty. A USB-C charger is unlikely to work, at least doesn’t work for the other V3 boards that I have.
Otherwise, you can power the board with 5V at the 5V pin or with 3.3V only through the battery header, keeping in mind that you should not apply external power in that case, as it’s not a battery you have connected.

My case seems more complicated. I am using a 5V 2.0A USB-A wall charger with USB-A <-> USB-C cable, exactly as you suggested. It should work according to your experience, but that is not my case.
About the supply with 3.3V why should I use the battery header? Battery is meant for 3.7V Lithium battery as fas as I understand, shouldn’t I use the 3V3 pins?
I am very puzzled. Supply was expected not be an issue at all…

P.S. even from PC I use the USB-A port and the same cable as above, but in this case everything works ok.

USB v2 power is a whole set of engineering issues with various sense resistors to negotiate how much power is required & how much can be delivered. USB-C takes this to a whole new level of complication.

Your PC will have the circuitry to support this. The cheap wall-wart style chargers could have anything inside and between them & HeltecDesign™️ anything could be going on and only 100mA is made available at the end of the wire.

If you have a branded USB power block, one that shipped with a more expensive device like a phone or tablet, try that to see how you fair. Ideally you want one with a USB-A socket so you can use a cable without any adapters and just end up with USB-C.