I had the same problem.
The command "AT+CWJAP="SSID","password" send 'FAIL'.
The SSID is 12 char.
The version is 0.9.2.4.
I have welding a capacitor of VCC and GND (470µF)
My module respond when i dont send the command "AT+CWJAP="SSID","password" but when i do :
wifiCommande( "AT+CWMODE=1",2)
wifiCommande( "AT+RST", 5, 'ready')
err = wifiCommande( "AT+CWLAP",10)
while err.count('ERROR')>=1:
err=wifiCommande( "AT+CWLAP",10)
err = wifiCommande( "AT+CWJAP?",30)
err = wifiCommande( "AT+CWJAP?",30)
while err.count('ERROR')>=1:
err = wifiCommande( "AT+CWJAP?",30)
Then, when he answers me (after more or less 50 to 100 request), I send "AT+CIFSR" and the module answers me an address IP...?
The mmodule is capricious!