I hit the same problem, the problem is about the algorithm to generate the secret_token. (For more information: https://stackoverflow.com/a/64114694/13799822) teamid is AppID clientid is bundle ID keyid is KeyID keyfile is the path to .p8 file This is the sample code for generating the secret_token. NOTED: *Seem the authorizationCode expirations is 5 minutes, so please make sure the authorizationCode is valid before making the request.* require 'jwt' Update these values with your app's information team_id = '' #AppID client_id = '' #bundle ID key_id = '' #KeyID key_file = './AuthKey_XXXX.p8' Define the JWT's headers and claims headers = { 	The token must be signed with your key 	'kid' => key_id, 	'alg' => 'ES256' } claims = { 	The token is issued by your Apple team 	'iss' => team_id, 	The token applies to Apple ID authentication 	'aud' => 'https://appleid.apple.com', 	The token is scoped to your application 	'sub' => client_id, 	The token is valid immediately 	'iat' => Time.now.to_i, 	The token expires in 6 months (maximum allowed) 	'exp' => Time.now.to_i + 86400*180, } Read in the key and generate the JWT ecdsa_key = OpenSSL::PKey::EC.new IO.read key_file token = JWT.encode claims, ecdsa_key, 'ES256', headers Print the JWT to stdout puts token