The clue is in your own detail: it started after the 2FA step took about five minutes, and switching accounts clears it. That points at a stale authorization request rather than anything wrong with the Etsy app itself.
What happens: Make opens Etsy’s authorize URL carrying a one-time client request and state. That request has a short life. While you hunted for the 2FA code it expired, and your Etsy session ended at the same time. Every retry after that re-sends the same dead request from the same still-open tab, and Etsy’s message for an expired or already-consumed authorization request is exactly the one you are seeing. It is not saying Make is an unknown app. It is saying this particular request is no longer valid. That also explains why a different Make account works: a fresh account generates a fresh request instead of reusing the stale one.
A sequence that usually clears it, without abandoning your main account.
First, in Make, delete the half-created Etsy connection from Connections, not just from the module. A pending connection keeps the old request alive.
Second, in Etsy, under Account settings, Your account, Security, remove anything listed for Make under connected or third-party apps. You said you cleared Connected Apps, so this may already be done.
Third, log out of Etsy completely and close every Make and Etsy tab. Do not retry in the tab that failed, because that tab is holding the expired request.
Fourth, log into Etsy first, on the account that owns the shop, and get 2FA out of the way so you are already fully authenticated.
Only then open Make in a new tab and create the Etsy connection. The authorize screen should now go straight to Allow with no login or 2FA step, which keeps you comfortably inside the request’s lifetime.
The general rule: finish an Etsy authorization within about a minute, and never retry a failed one by refreshing the old tab. Always start it again from Make.
If it still fails when you are already logged in and 2FA is behind you, that rules this explanation out, and it is worth a support ticket with the timestamp and the full URL of the authorize page.
Kane - Northpeak Automation