the account of partition aws-cn grant access to partition aws

my service build in aws-cn and want to grant access to client based on the account of partition aws by apigateway. but I failed to set the policy in iam policy. my actions is: create iam policy, but the aws-cn can`t set aws-cn arn, the error message is : This policy defines some actions, resources, or conditions that do not provide permissions. To grant access, policies must have an action that has an applicable resource or condition. For details, choose", are there other way to grant access,thanks!