If you get a denial such as CO197-Contractual Obligation Precertification / authorization / notification absent, this means that when the claim was submitted the authorization was omitted.

How would you resolve a denial for no authorization?

If the denial reason was “no pre-authorization,” ask the plan to back-date one. If they will, resubmit the claim with a note including the new auth number. If they won't, appeal.

What happens if insurance denies prior authorization?

If you don't use a health care provider in your plan's network, then you are responsible for obtaining the approval. If you don't obtain prior authorization, the service or supply might not be covered or you may need to pay more out-of-pocket.