Ah, i see. Now i understand, why i need to return ESP_OK;
Thanks to you, guys!

So i have to work with some kind of ESP_ERROR_CHECK? In example: ESP_ERROR_CHECK( esp_wifi_start() ); or wifi_init_config_t initconf = WIFI_INIT_CONFIG_DEFAULT(); ESP_ERROR_CHECK( esp_wifi_init(&initconf) ); ? Or is it more for functions like ESP_ERROR_CHECK( esp_event_loop_init(event_handler, NULL)...

Might be a stupid question, but i'm new i all this esp32 sdk programming. What exactly is the event_handler in this function: Why should i implement this function in the beginning of my script?

Touché. That was stupid question.

So the internal 8 MHz oscillator with calibration is supported.

.. and also included in the esp 32 wroom?

In the esp32 datasheet (https://espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf) are 4 oscillators: Internal 8 MHz oscillator with calibration Internal RC oscillator with calibration External 2 MHz to 40 MHz crystal oscillator External 32 kHz crystal oscillator for RTC with ca...

If this is not possible, is there a way to reduce the clocking speed?

Someone know, how its possible to overclock the esp32 dev board?