u/Own-Base-9036

Yesterday I had a 65+ customer who wanted to do a flu shot. When I ran the RX with her Medicare part D insurance, I got a rejection saying use part B. When I ran it with part B, it rejected again saying HMO coverage exist (or something like that). We did not have this issue in the past. Does anybody know what it is about? Does it mean we are out-of-network?

Thank you in advance!