iphone connects to wrong wifi

Hi, anytime I connect the iphone to a new wifi, the phone always tries to connect to wifi i once used in some train… i have to cancel the connecting and choose once more the correct new one.

the wrong wifi is not listed in the known connections so i cannot change the configuration of make the phone forget it…

its like it since i used the train wifi year and half ago, no update helped… i have even tried to go to train, connect the same wifi and forget the connection, changet the autojoin settings, but still nothing has changed and the problem continues…

thank you very much for advice