Refreshing cache of AWS FileGateWay

Question

I am trying to refresh cache on AWS FileGateway. I have built the AWSStorageGateway using AWSStorageGatewayClientBuilder object like this -

AWSStorageGateway awsStorageGateway = AWSStorageGatewayClientBuilder.standard()
                .withRegion(region)
                .withCredentials(new AWSStaticCredentialsProvider(credentials))
                .build();

Also, I am using this to build the ARN -

RefreshCacheRequest refreshCacheRequest = new RefreshCacheRequest();
refreshCacheRequest.setFileShareARN("arn:aws:storagegateway:"+region+":"+awsId+":"+shareID); 

ARN is of the format,

arn:aws:storagegateway:region:account-id:share/share-id 

Finally, I am refreshing the cache like this 0

awsStorageGateway.refreshCache(refreshCacheRequest);

I am getting this exception -

com.amazonaws.services.storagegateway.model.AWSStorageGatewayException: User: arn:aws:iam::12345:user/system/func-user is not authorized to perform: storagegateway:RefreshCache on resource: arn:aws:storagegateway:region:account-id:share-id (Service: AWSStorageGateway; Status Code: 400; Error Code: AccessDeniedException; Request ID:request ID)

Am I missing anything here?

I am pretty sure IAM access key which I have has the previlages.

PS - account-id which I have given is the Access Key of IAM