Of all the decline codes a subscription business meets, "do not honor" is the one that feels most like a personal judgement and means the least specific thing. It is the issuer's generic refusal — a single code standing in for a drawer full of unrelated reasons: a fraud screen tripped, a card reported and replaced, an account under review, a velocity rule, a restriction the bank will not explain to you and often will not explain to its own customer either. Treating it as one problem is the first mistake. It is a category wearing a code's clothes.

What the code rules out, and what it does not

A do-not-honor is not a hard decline in the permanent sense — the card is not necessarily dead, and the same card sometimes pays weeks later without anything visible changing.…