Do I say "Au convaincre" or "convaincre lui" To mean I convince him

Question

Does the "le" join to "à" to form "au" in "Après Lin a échoué à convaincre" or am I wrong?

Answer 1

In this case, à does not join with le because au is the contracted article.

But in the phrase,

Lin a échoué à le convaincre

le is not an article but rather a personal pronoun (Lin convinced whom? him = le). It therefore remains à le.