Nokia :: Gmail For Mobile Application With 6303 / Doesn't Work

I`m surprised that Gmail for Mobile app doesn`t work on my Nokia 6303, though it did work well with my old 6151 (and the operator is the same, nothing has changed except the phone model). It downloads properly, but when I try to open the Gmail, it keeps constantly asking for internet connection. But the connection is there! I press the "yes" but it keeps asking till finally tells to check the connectivity... And I have no problems with browsing the internet or opening and using my email accounts via web. I checked my settings but they seemed to be fine. But Gmail just doesn`t work, though I`ve tried several versions besides the newest one.