ServiceNow HTTPS ERROR - [ERROR CODE: -1 ] No issuer certificate found

This error occurs when ServiceNow trying to make outbound HTTP calls to another server

ServiceNow uses OPENSSL to validate the server certification 

Resolution

There are two options to resolve this: 

(1) Clean up the endpoint so that there are no more certificate errors seen when executing the: openssl s_client -connect <endpoint hostname or IP address>:<port> -showcerts
(2) To ignore these certificate errors (i.e. remove the tighter certificate standards) add this system property to the instance: 

Table Name :

sys_properties

Name = com.glide.communications.httpclient.verify_revoked_certificate 
Type = true|false 
Value = false 

https://security.stackexchange.com/questions/112768/why-are-self-signed-certificates-not-trusted-and-is-there-a-way-to-make-them-tru