The layman (like me) is probably only upvoting this because of the controversy around the ABC conjecture where there's supposedly a "proof" since 2012 but nobody in the mathematics community believes it:
https://www.quantamagazine.org/titans-of-mathematics-clash-o...
It's not that no one believes it, the problem is that this particular possible proof of ABC conjecture came from 1000-1500 pages of dense, new math. As in, the proof writer invented some new math, and from that new math he claims he can prove ABC as a sort of side-project to his goal of furthering his new mathematical area. No one else can really understand his proof because it would take years to study the text behind it, but a few are trying and may have found a hole in his proof. I am not sure what the status is since the article you linked, but as with huge code bases I am pretty sure that there must be at least one error in those 1000-1500 pages of math.
That's not an entirely accurate summation of the current state of affairs, as I understand it.
At this point, several people who have tried to follow the proof have all pointed to the exact same step where their attempts came undone: Corollary 3.12. And it's become agreed by everyone that if this doesn't hold, the proof doesn't hold.
Yea, it's been a while since I followed this, at least 2 years now, so it makes sense to me that an error has been found. This proof seems very complex to me at 1000+ pages.