I am having this issue for a week now. I have one In-App Purchase working fine in Sandbox, simulator on real device and on Test Flight. Once app submitted to app store it get rejected. The reason of rejection first time, no items available for purchase (i.e didReceiveResponse:(SKProductsResponse *)response, returns 0 product). The subsequence submissions of app 4 times get rejected due to transaction failed SKErrorUnknown. My contract is signed, In-App purchase clear for sale in all countries. Test flight working fine with more than one apple account. I also once tried deleted In-App purchase item and recreated with new ID but no luck still app rejected due to SKErrorUnknown. I have renewed my account 8 days ago, not sure if this is a reason and to solve this issue. If anyone faced this issue, please let me know how did you solve it. Any support or hint.