Invalid CA Certificate File Error When Connecting to Back-End Resources

The following error will be displayed to a user's browser page when attempting to reach a back-end or downstream HTTPS server whose SSL certificate is not trusted in the appliance's list of CA certificates:

Error Invalid CA certificate file - (SSL certificate problem, verify that the CA cert is OK)

To correct this error you can either import the CA's signer's certificate in AMC > SSL Settings > CA Certificates > Backend server root certificates

OR

Disable the SSL certificate check in AMC > Services > Configure Web > Validate SSL server certificates