Some times ago, I experienced internet connection problem when used 3data from the operator 3 (“Tri”) as my Access Point. I always got “Unauthorized Internet access. Please check your APN” message whenever I tried browsing the Internet using Nokia built-in browser, but it occured sometimes when I used Opera Mini.
But then, Alhamdulillah, the solution is appeared here.
Go to Settings | Connectivity | Settings | Network destinations. Then configure the ‘3data’ access point. Leave the ‘Proxy server address’ blank, and fill ‘Proxy port number’ with ’80’ (without apostrophe).