Recieving invalid_grant, but only during App Store Review

We have our app, which has sign in with apple. We implemented it some time ago. It's been working generally fine. We receive some small amount of invalid_client responses which we are unsure about, but most response seem to be correct.

We've recently gotten rejected multiple times because the reviewer cannot sign in with apple. When checking the logs, it appears that the app reviewer, and only the app_reviewer receives invalid_grant . We've been unable to reproduce this issue so far. We've looked at the requests and nothing seems suspect.

Is there anything at the account level which can cause a user to receive invalid grant? I've tried creating an account outside the countries we support, and it seems to work fine.

Our requests look like this:
Code Block
curl -X 'POST' -d 'client_id=<our_app_id>&client_secret=<secret>&code=<code>&grant_type=authorization_code' -H 'Accept: application/json' -H 'Content-Type: application/x-www-form-urlencoded' 'https://appleid.apple.com/auth/token'


These requests are coming from our native app. But it appears to happen regardless of whether we include a redirect_uri or not.
We have the same issue. The invalid_grant error response only occurs in Apple reviewers' account.
May I know do you conquer the problem and pass the review now?
Thanks a lot.
I came across this post and I'm having the same issue as well. Did you manage to figure out what the issue was as I'm now stuck in being unable to have my app go past the review stage?
We have the same problem. Not sure how to fix it but the user signs in once, they have an account and signs in again which fails
Same happened to us last review for two times consecutively, anyone managed to find out what is the problem?

On our phones it works just fine :(
FYI we solved this problem. It turned out we did in fact have a retry hidden within some of our backend code that was retrying using the same token that then caused this error. As for why it only really seemed to affect the app reviewers, we aren't really sure. The current hypothesis was that perhaps there was something about the accounts of these users that caused the API to be slower to return a response that then timed out and caused the retry.
We solved the problem. We requested the review team two things.
・if the apple account is connected with our service, disconnect it and try to sign up again.
・if the apple account is not connected with our service, user another apple account and try to sign up again.

Then the review passed. I guess the connection between the apple account and the service had something wrong. It might be solved by reconnection.
Recieving invalid_grant, but only during App Store Review
 
 
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