I used my Button without problems in one WIFi network. Now after some time I startedt to configur it for another WiFi it does not accept access from my tablet or mobile. Still the bttnconf - is up and running and signal level is ok.
(Sorry for the typos above:-) That problem may have been actually because I have updated my Nexus 7 Android tablet to Lollipop 5.0 which has wifi issues. Now configuration succeeded from iPhone.