No Wifi connection although AP-Mode is quit

[Riichboy]

Hi,
first of all, thanks for sharing this great project and all the work that was so far done into it!
This is my first ESP8266-project, I am using the NodeMCU V3 board and WS2812B LED-stripe.

My problem is, that I don't get a Wifi-connection in the last step of the setup-procedure. I can save the WiFi information for my own network using the MCLightning network, the ESP leaves the AP-mode afterwards (indicated by the onboard LED going from blinking to steady lightning), the connection result is 3, but then I don't find the ESP as WiFi client on my WiFi-router :-(

I'am stuck on this now for a long time, double checking all settings and installations, so thanks a lot if s.o. can help me with that!

The output from the Terminal is:
"
*WM: Sent config page
*WM: Request redirected to captive portal
*WM: Request redirected to captive portal
*WM: WiFi save
*WM: Parameter
*WM: strip_size
*WM: 7
*WM: Parameter
*WM: led_pin
*WM: 16
*WM: Sent wifi save page
*WM: Connecting to new AP
*WM: Connecting as wifi client...
*WM: Connection result:
*WM: 3
Should save``
"