I got the QuickBooks Online API apparently working perfectly in a custom connector, but I have another API that is returning the following error:
Failed to refresh access token for service: oauth2. Correlation Id=..., UTC TimeStamp=..., Error: OAuth 2 access token refresh failed. Client ID and secret sent in form body.. Response status code=BadRequest. Response body: {"error":"invalid_grant"}
It seems that something is happening with the refresh token request that is causing it to fail, but that happens in the background. We have no visibility into that request or the response, the OAuth2 custom connector handles that for you and it just works. Or so it did with the QBO API. This other API is more stubborn and I suspect it has something to do with the way they want their requests formatted. I'm not sure what Postman settings would affect this, but for instance these three settings in Postman's >Authorization tab seem like possible culprits:
Add authorization data to [Request URL] vs. [Request Headers]
or
Authorize using browser [y/n]
or
Client Authentication [Send client credentials in body] vs. [Send as Basic Auth header]
I am using the exact settings in the broken custom connector as what I used for the working QuickBooks Online custom connector, except with the base URL, auth URL, token URL, refresh URL, request URLs, client ID, and client secret all being unique to each API obviously. Other than those, everything else is exactly the same. API #2 works great for 20 minutes and then its access token expires and I get that error above^.
Any Power Platform wizards out there? @v-bacao-msft
Here's my earlier post in a different thread
