What sort of rest periods are you taking between each set? What part of the press are you struggling most with? If you're failing with the initial push-off then you could incorporate some pause presses into your workout (make sure you drop the weight a bit when doing these). If you're failing just before lockout then it could be your triceps need building up a bit. Speaking of contributing muscle groups, a strong back and shoulders will help form a good base so make sure those are being trained regularly. Finally, I'm assuming you've covered this already but make sure your form is spot on. Retract your scapula, bench with your arms at about a 45-60 degree angle to your body, engage your glutes and use leg drive.
I usually rest (as I can feel the last rep being tougher so I have more rest)
1.5 min
2 min
3 min
5 min
6 min
It feels like I just run out of steam.... the weight is liftsble because I can do the other sets....
I usually know on my 4th that the next one is not gonna go and I can just push and push and it goes nowhere. It’s towards the bottom of press...