I have same problem. This gateway issues are killing gmail, yahoo mail and other similar services. I sent them the email complaint to customer care email for this reporting this problem. Pls you send them one email as well so they don't ignore... here is the email address ->
care@uninor.in
---------my email-------------
Dear Sir/Madam!
I making problem report regarding your GPRS service provided to prepaid users in
Kolkata area! [I'm not sure if this problem exist for global india]
Please fix persistent issue with the "gateway timeout's". It makes Uninor GPRS internet impossible to access GMAIL, Yahoo mail web services [which using excessively "ajax" web technology and therefore breaking on Uninor's Gateway timeouts]... in other words this services and similar are impossible to use and are not working correctly. Other mobile providers like TATA.docomo... are not having issues with mentioned above! Also I found many Uninor prepaid users on internet complaining for the same. Please take this message to your technical department and resolve it ASAP as this is very BIG BIG BIG technical bug on your side and you may loose many existing and new subscribers as many users don't like this things to happen.
Regards