WiFi - Authentication problem

[Alanjune]

WiFi was working fine until 10am this morning, since then i have been unable to connect, when i enter the password to connect, it shows as saved, then shows as 'connecting, followed by 'Authentication problem', there is nothing wrong with the router etc. as work colleagues are using the same WiFi and it's fine for them, i have tried using the Sony PC Companion, it said my phone is up to date, so i done a repair/restore, i am still receiving the message "Authentication problem" when trying to connect to the WiFi, how do i fix this?

[Samuel1]

Can you connect to other WiFi networks?

[Alanjune]

i receive the same error - Authentication problem

[Samuel1]

Alright. Did you try to repair the phone software? (PC Companion -> Support Zone -> Update phone software -> Repair phone software)

[Alanjune]

I've just tried the 'repair' option, when i try to connect to the wifi now it says 'Connecting...' then jumps back to saved, followed by 'Connecting'...

[Samuel1]

Sounds really strange. As the issues still remain I think that this needs to be examined and fixed at a repair center. For more information about how to submit your phone for repair and where, contact your local support team.

[robertavarghese]

I am also having the same problem, I did not try repairing the phone....it can connect to other wifi but not to my office wifi, but my colleges can connect. I change all settings in router but doesn't connect, it says authentication problem.

[Curnow1]

What about doing a factory reset? 

[Uliwooly]

@robertavarghese 

That's a good idea @Curnow1

PC Companion (PCC)

Bridge (for Mac)

Alternatives on How to backup Xperias

http://talk.sonymobile.com/thread/36355

[robertavarghese]

I did a factory reset after I receive this phone, as I got it from my brother and he was using it with lollipop, is the close all button back in 5.0.2...23.1.1.E.0.1?