WiFi.softAP only works when passphrase is 0, in esp8266 it also works when passphrase is "". In WiFiAP.cpp on line 104 should change from: if(passphrase && (strlen(passphrase) > 63 || strlen(passphrase) < 8)) { to: if(passphrase && (strlen(passphrase) > 63 || strlen(passphrase) < 8 || strlen(passphrase) == 0)) {