esp_wifi_set_config() returns ESP_ERR_WIFI_PASSWORD

[MatsWebjorn]

I've created a project based on v5.4.2\esp-idf\examples\wifi\getting_started\softAP. Using the default configuration the samlpe works fine. But when I change the Wifi password to "vargen" esp_wifi_set_config() fails with ESP_ERR_WIFI_PASSWORD.
Unfortunately esp_wifi_set_config() is not available in source so I can't step into the code to see why it fails.
After several tests it turns out that password must have at least 8 characters. But where is this defined? And how come that menuconfig has checks for length?

[nopnop2002]

The WPA2 security protocol mandates a minimum password length of 8 characters.