schufti wrote:Maybe from some earlier sketch. WiFi.persistent(false) doesn't remove allready stored credentials neither replaces them or prevents reconnect with stored values; it just does not store the actually provided ones in flash on successful connect.
Change the PW on your WiFi and see if it still reconnects at startup.
Yes, that might be the reason. I will check that but only after New Year.
schufti wrote:It is not regarding the board you use, it is the Version of ESP-Package (look in board-manager).
Thank you, I'll check that too.