In our Outbound Messaging Delivery Status we are receiving an error message "javax.net.ssl.SSLPeerUnverifiedException: peer not authenticated"

But, we have a valid cert as distinguished here:
https://www.sslshopper.com/ssl-checker.html#hostname=admin.clearcareonline.com
This shows that we have a valid cert chain.
https://developer.salesforce.com/page/Outbound_Messaging_SSL_CA_Certificates
starfieldclass2ca is listed and is in the chain
openssl s_client -connect admin.clearcareonline.com:443 |egrep -i starfield
s:/C=US/O=Starfield Technologies, Inc./OU=Starfield Class 2 Certification Authority

And, both the certs on Salesforce and our Site have a matching SHA1.

What needs to happen to ensure that Salesforce accepts our cert?

In our Outbound Messaging Delivery Status we are receiving an error message "javax.net.ssl.SSLPeerUnverifiedException: peer not authenticated"

But, we have a valid cert as distinguished here:
https://www.sslshopper.com/ssl-checker.html#hostname=admin.clearcareonline.com
This shows that we have a valid cert chain.
https://developer.salesforce.com/page/Outbound_Messaging_SSL_CA_Certificates
starfieldclass2ca is listed and is in the chain
openssl s_client -connect admin.clearcareonline.com:443 |egrep -i starfield
s:/C=US/O=Starfield Technologies, Inc./OU=Starfield Class 2 Certification Authority

And, both the certs on Salesforce and our Site have a matching SHA1.

What needs to happen to ensure that Salesforce accepts our cert?