I have the exact same issue and setup as the OP. All configured as per the Apple docs. Consistently getting zero products returned. Plus, on real device Settings > Developer > Sandbox > Manage > Initiate Purchase fails with incorrect Bundle and/or Prodict ID, but says "Could not complete at this time, please try later" with correct Bundle & Product ID. Later being 3 days so far for me... Any help please?

ok I've managed to get it all working correctly (following from my earlier comment) I went through the checklist posted by Apple Engineer above the TechNote checklist at: TN3186: Troubleshooting In-App Purchases availability in the sandbox | Apple Developer Documentation The thing that was blocking the products being returned in array was having not filled in ALL of the details needed on the AppstoreConnect > Business page Namely payment agreement, bank account, tax status statements etc. After I had done that, about 2 hours later, all my test calls and purchasing views were working and the whole purchase flow as usual for an iOS device See attached for Sandbox confirmation Apparently all "Business" info is needed even for Sabdbox transactions. HTH folks. Shout if I can add any more info