The solution-users.properties file in vRealize Business has the configuration that points the application to the certificate it is using. Unregistering vRealize Business from vRealize Automation should delete this file. Upon successful registration, this file is newly created.
This issue occurs when a new certificate is generated in vRealize Business without unregistering it from vRealize Automation. The vRealize Business application points to the old certificate instead of a new one.