57% could be :
It either does not get a dhcp ip from the server.
It has problems witha wpa / wpa2 password.
It is missing the mac adress in the allow list.
I have to use wpa2 personal + pass phrase + automatic wpa2 type (aeis or tkip just leave at automatic) something like this and then it works.
If you can disable any blocking like mac adress filter and wpa type so that you can see if it can connect normally without them active. If it works then you have to check mac / wpa type and correct pass phrase , if not then the router signal is weak or the router needs a reset / restart after 2 mins. disconnected. Might want to get latest firmware for wifi router as well.
Alternatively is there a way to check the signal strenght in windows / another linux distro / SL you would need for a good connection at least 20 difference in numbers from signal to noise. 64 signal 83 noise then it can cope very well / good speeds for internet but jsut reasonable for pc to pc lan type via wifi.
Hope something here helps. Sry my brain is a bit slow now will post if I remember something else.