Hi All I have write below code but not able to pass I donot understand where is the issue 

So can any one tell me where I am doing wrong here

#Remote Site Setting
Remote Name - > SOAP
URL -> https://th-apex-soap-service.herokuapp.com

#Error
Challenge not yet complete in My Trailhead Playground 1
Executing the method 'getAccount' from the Apex class 'AccountManager' failed. Either the service isn't configured with the correct urlMapping, is not global, does not have the proper method name or does not return the requested account and all of its contacts.

#Code
@RestResource(urlMapping='/Accounts/*/contacts')
global class AccountManager {
    @HttpGet
    global static Account getAccount() {
        RestRequest req = RestContext.request;
        String accId = req.requestURI.substringBetween('Accounts/', '/contacts');
        Account acc = [SELECT Id, Name, (SELECT Id, Name FROM Contacts) 
                       FROM Account WHERE Id = :accId];
        return acc;
    }
}

#Test Class
@isTest
private class AccountManagerTest {

    private static testMethod void getAccountTest1() {
        Id recordId = createTestRecord();
        // Set up a test request
        RestRequest request = new RestRequest();
        request.requestUri = 'https://na1.salesforce.com/services/apexrest/Accounts/'+ recordId +'/contacts' ;
        request.httpMethod = 'GET';
        RestContext.request = request;
        // Call the method to test
        Account thisAccount = AccountManager.getAccount();
        // Verify results
        System.assert(thisAccount != null);
        System.assertEquals('Test record', thisAccount.Name);

    }

    // Helper method
        static Id createTestRecord() {
        // Create test record
        Account TestAcc = new Account(
          Name='Test record');
        insert TestAcc;
        Contact TestCon= new Contact(
        LastName='Test', 
        AccountId = TestAcc.id);
        return TestAcc.Id;
    }      
}