"Tu fais confiance à moi" is wrong? How so?

Bonjour Nicholas !

In the case of indirect objects - complements to the verb introduced by a preposition "à" or "de" - following the pattern "à + stress pronoun", in French they need to be replaced altogether by indirect object pronouns: "me, te, lui, nous, vous, leur".

Here are links to our related lessons:
https://progress.lawlessfrench.com/revision/grammar/when-to-use-me-te-nous-and-vous-as-me-you-us-and-you-direct-and-indirect-object-pronouns
https://progress.lawlessfrench.com/revision/grammar/when-to-use-lui-and-leur-to-replace-specific-people-with-him-her-and-them-indirect-object-pronouns

I hope that's helpful!
À bientôt !