UPDATE: Pinterest support got back to me and confirmed that the Ver. 1 API is broken. Instead of fixing it they have offered to expedite my new app approval. I heard back from them quickly, but it's been almost a week now from submitting the materials they requested for the new app. I submitted them the same day they asked for them.
I'm having essentially the same problem that this user was:
Pinterest Authorization failed
This is an app that has been approved and working for years and we have started getting this error just in the last week when sending a GET request to https://api.pinterest.com/v1/me/boards:
{"status":"failure","code":3,"data":null,"message":"Authorization failed.","endpoint_name":"get_own_boards"}
In the header I of course have the access token, which I had just received from Pinterest successfully:
"Authorization: Bearer Ah-ObYMmQFc-(REDACTED)"
The other strange wrinkle is that when I try the same request but with the access token from the Pinterest user that owns our app on Pinterest it works as expected.
I know that this has been an issue previously, but I didn't see anyone reporting it currently. The other thing is that this endpoints are being deprecated, but the new ones are only in Beta. I have an application in for the new API, which I would love to switch to, but I don't know how long that will take. Can anyone please help with this?