This article explains an issue where the device throws commit errors for any config change after the user deletes existing self-signed certificate.

You will se an error like the one shown below when you try to make any config commit on the device:

error commit-confirm: [edit services ssl termination] profile SSL-Test: ERROR: Unable to get cert type for server certid: JuniperCert

This is an expected behaviour if you delete the certificate but miss to delete any of the knobs where the same certificate is being called or referenced. In this case you need to delete the ssl termination profile where the certificate is being referenced in order to clear the commit error.