You have used a word inappropriately, or used the wrong preposition with a verb. Check a dictionary. Usage errors include non-standard constructions or word choices that, while not necessary incorrect by the laws of grammar, are simply not used by native English speakers.
“as such”
“as such” is a commonly misused phrase. It only works if it refers back to a noun.
Here’s a correct example: “Janelle is a gardener; as such [i.e., as a gardener], she often has dirt under her fingernails.”
Janelle Jenstad 