To top that up, it's fact that there have been "proves" that were wrong (or maybe that's just my believe? :^]) even for a long time.
Hence, I think we can say that there are 4 options for a theorem:
1) Some mathematician believes the theorem is correct (but can't prove it)
2) Some mathematician believes the theorem is incorrect (but can't prove it)
3) Some mathematician believes the proof of a theorem is correct
4) Some mathematician believes the proof of a theorem is incorrect
Proving that a proof is correct is kind of meaningless. At that point it's all believe anyways.