connecting kindle to WiFi

I have an older kindle.  It was working great, I could down load books from Amazon everything.  About 2 weeks ago it stopped connecting to the WiFI.  I have done the trouble shoot the modem, I have entered the username and password into the kindle about 30 times it scans looking for it and then nothing.  It does come up with WIFI connections of my neighbors??   On Xfinity it has my device as a Not used device. What do I do?