I'm trying to complete the "Set Up Single Sign-On for Your Internal Users" Trailhead challenge, and was able to execute the description of the challenge successfully. However, I'm getting the following error when checking the challenge on Trailhead:
 

Challenge Not yet complete... here's what's wrong: 
Could not find SAML Enabled in your org's setup audit trail. Make sure that you have 'SAML Enabled' checked under 'Federated Single Sign-On Using SAML' in your org's 'Single Sign-On Settings'.

I've reviewed the settings, and "SAML Enabled" is true, and I'm connected to the right org when doing the challenge. Has anyone else encountered this?

I am receiving weird error while attempting Test Callout (#5), it is giving below error.

Challenge Not yet complete... here's what's wrong: 
The 'WarehouseCalloutServiceTest' class does not appear to be using the 'WarehouseCalloutServiceMock' mock callout class.

But my WarehouseCalloutServiceTest is calling the mock class and it shows 100% code coverage for WarehouseCalloutServiceMock class after running the test. 100% coreage for mock class shows that I am using the class. So,  Can anyone help in figuring what can be the issue.