UHC and Emblem both want to mess my wife over for our upcoming birth

Hi, I had my first polio vaccine at a CVS MinuteClinic 2 weeks ago and put down my Aetna insurane (Elect Choice Open Access through employer). The doctor at the time says the claim will probably be denied at first but don’t worry you won’t have to pay. My partner did it a few days earlier than me and his account got a claim with $115 “amount billed”, $39 “your plan paid” and $0 “amount you may owed” so I thought things will be fine.

This morning I checked my Aetna account for the new claim and I got a claim with $115 “amount billed” but this time $115 “amount you may owed” and claim status “Denied”. I called up Aetna and the woman on the phone was definitely nice but she said I would need to get precertification (? I’m not exactly sure what this is but searching on the internet says precertification is done _before_ the appointment).

r/HealthInsurance, what should I do? and what should I worry about when getting my second dose of Polio vaccine?

Edit: Thank you to those who have answered so far. I can confirm that the MinuteClinic I went to is definitely In-Network, and under available services there is “Vaccinations (Non-COVID)” (which what polio vaccine was listed under on minuteclinic website)