Wifi Authenitication problem

[cj05]

Cannot connect to wifi.  Mobile can see the modem but when trying to connect I keep getting the message "Authenitication problem".  Xperia Z2 mobile.

[Thommo]

This can often be fixed by rebooting the router/modem and can often be because the router/modem is an old model and not compatible with the various new wifi frequency's

[cj05]

Thanks Thommo, have tried that several times and modem is only a few months old so it must be some other problem.  Mobile has been working fine up until last week, so not sure what has happened.   Will probably have to take it back to the supplier.  Thanks for your suggestions.

[Thommo]

Have you tried forgetting/removing the paired router and reconnecting?

Edit: Is this only happening on the router in question or on all - If it's just the one in question then it could be the routers built in security blocking you

[cj05]

Yep have removed and paired several times without success.  As I live in a remote area have not been able to try another modem, will do this next time I go to town.  Thanks again.