Driver door won't open from outside.... not the handle

As the title says....I Put another handle on but no joy. I kept the remote bit so it was the same, i thought if i fitted the one from the other car I'd maybe need to get it programmed in. It opens from inside fine.
Could it the actual metal lock/ catch on the edge on the door that's buggered, if so why would still open from the inside though..
More likely a rod is not connected properly from the handle to lock.
You should be able to open it by pushing the lever the rod goes on to. If it doesn't work then look at the lock or just replace it.