Mobile Wifi問題

我依家用緊 Sony Ericsson Xperia Neo.
我有一個pocket Wifi用黎比部電話上網.
之前我用依個wifi上網係冇問題ga, 但係唔知點解依家用依個wifi上唔到網同用唔到facebook apps. But other apps which needs internet can run.我都試過用學校個wifi上網, 又上到wor...就係用自己果個上唔到。咁我可以點做呀??

Can anyone help?