Have you setup a truststore and then trust SAM as an application that can connect to Ambari? I have not set this up but not setting up a truststore and "trusting" SAM can be a reason for your error. Check troubleshooting in the following link:
I did created a truststore for queue manager view. But I believe although the truststore is located on Ambari server, by importing Ambari HTTPS cert to the store it is actually used by Ambari views to connect to Ambari HTTPS server. It is not really for other client like SAM.