I'm going to go out on a limb and guess you're new to this? The pitlane at Sepang is not the easiest to find if you don't know where you are going (especially from the cockpit or T-bar). The pit entry is on the outside of the last hairpin. About halfway through the turn it will be straight ahead.
I think there are 2 little green/white bollards marking the pit entrance, but with so much green around they're not so easy to spot, especially if you are unfamiliar with the track.
Some red/white bollards might be more appropriate .....