LawesJack

Hi guys, I'm having problems intonating my guitar on the low e and string I can't tighten the bridge screws any more and my tuner is still saying I'm a little bit sharp and on my b sting I can't loosen the screw any more and when I hit the 12th fret b string I'm hitting an a sharp so it's still really out of tune. What do I need to do. All the other strings are fine and intonated properly. Thanks