To resolve the issue, import the Ambari certificates to the Ambari truststore. To import the Ambari certificates, do the following: 

STEP 1: 
Get certificate from ambari-server 
echo | openssl s_client -showcerts -connect <AMBARI_HOst>:<AMBARI_HTTPs_PORT> 2>&1 | sed --quiet '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > /tmp/ambari_certificate.cr 

STEP 2: 
Get path of ambari trustore and truststore password from Ambari properties 
cat /etc/ambari-server/conf/ambari.properties |grep truststore 

As per your ambari.properties below is the path and password :-
ssl.trustStore.password=refer from ambari.property file
ssl.trustStore.path=/etc/ambari-server/conf/ambari-server-truststore

STEP 3: 
keytool -importcert -file /tmp/ambari_certificate.crt -keystore <keystore-path> 

STEP 4: 
ambari-server restart