Medicare denying claims, reason CO-45

I've noticed a "trend" w/ Medicare for 2020...we've not rec'd payment on any of our claims, being denied for reason code CO-45. (I am billing w/ all the new/updated ID #'s). I also have a handful from the end of 2019, that were denied for the same reason. Should I change the condition/diagnosis codes more frequently?

re: Medicare denying claims, reason CO-45

CO-45 is a reason code is telling you it is the contractual obligation of the provider and the patient cannot be billed for that amount. It is over the amount the provider is contracted to accept and exceeds the maximum allowable or contracted fee arrangement. The bottom of your explanation of benefits should give you an explanation of the reason codes reported.