403/401 is returned (permissions and scopes)
How to isolate the cause when an API call returns 401 or 403. Explains the typical cases: invalid token, insufficient scope, no store access permission, and User-scope review not passed.
The developer portal is not shown while on the Free plan
What to check when the ReceiptRoller developer portal is not shown. Explains what to do when your plan is Free, switching business accounts, and the timing of when the display updates.
Webhook is not being delivered
How to isolate the cause when a Webhook does not reach your receiving endpoint. Walks through checking, in order, the endpoint settings, subscribed events, reachability, signature-verification failures, and firewalls.
app_not_approved is returned for User-scope calls
What to check when using a User-scope results in an app_not_approved error. Explains development with a sandbox slot, applying for review, and the flow from sandbox to production.
Cannot obtain a token (authentication error)
How to isolate the cause when you cannot obtain an access token. Explains the representative errors — invalid_client, invalid_grant, redirect_uri_mismatch — and what to do about them.