Why is 会える conjugated as 会えなくなった?


So I kept searching on the net about 会える conjugation but nothing comes up. Why
is its past negative conjugated as なくなった? I heard this on an anime by the way
and wondered why it wasn't written as 会えなかった?




会えなくなった -> 会えなく + なった

会えなく is the adverb form of 会えない

なった is なる in past tense

> (It) becomes not being able to meet. -> (We) stop being able to meet

