Over on the Amazon Kindle forum, users sometimes post about WiFi issues and getting "authentication problems"
SO - what would be the issue ? and the 20 questions to ask ?
ok.... so you have a Kindle Fire HD 6" - What brand & model is your WiFi Access Point ? What type of Security is being used - WEP, WPA, WPA2 ? What mode of operation - 802.11 B, G, A, N, B/G mixed ? If using N - are you using 20Mhz or 40Mhz channels ?