Error: Doesn't match any valid certificate/private key pair in the default keychain

I am trying to upload my first app on the App Store, but it isn't working.

I have followed every step I found on developer.apple.com, and in other resources. I have created certificates which are valid, made a provisioning profile, and app ID as well, 开发者_StackOverflow中文版but I get the same error.

I have compared my code to other code on another system which is creating a binary for that code. The main difference which I notice is the entitlement.plist file. I have something like "boolean" and "checkbox" whereas in the other code I found an array and something regarding keychain access. Help me through this problem please. Thanks. Tell me if I'm wrong regarding the .plist file and if that is a problem then tell me how can I fix that and from where. Thanks again. Waiting...

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Make sure you've installed the Distribution Certificate from iTunes Connect, and selected the right profile...

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