New lock brought for a pvc door fitted as stated will lock when open but not when closed

The lock may be ever so slightly different and may be catching on the plate on the frame, is it an exact replacement or a cheap alternative ?

The door needs lining up properly as its out of synch, needs to be toe and heeled/ adjusted. Get someone who knows what theyre doing.

As said above, your doors out of alignment and needs doing properly

Door needs adjusting at the hinge side, it's nothing to do with the new cylinder you put in, purely coincidence. Any locksmith should be able to sort it in about 15 mins.

Common fault, when you lift the handle the rollers/cams should slide into the keeps as should the latch and deadbolt. If these do not align then you will not be able to fully lock the door. A locksmith can adjust the door where needed and should take no time at all.

Your door needs to be alined very easy job

This seems to be a door alignment issue not a problem with the lock, your door may have dropped over time it’s a common problem.

An alignment issue. The rollers, hooks ect are not lined up properly with the keeps (holes in the frame). Most PVC hinges can be adjusted with an Alan key. It is a relatively easy fix but I suggest hiring a professional.

Normally, the problem is related to an adjustment issue or could be a fault with the gearbox. I would suggest contacting a licensed locksmith.