While troubleshooting an issue with the Portal's SSL certificates being invalid, I inadvertently deleted the out of the box SAMLCERT Self-Signed SSL Certificate found under Portal Admin -> Security -> SSLCertificates. I clicked on the SSL Certificate and clicked delete.
I've been searching for documentation for information/instructions on how to regenerate that certificate without success. Does anyone know if there are any scripts or utilities that I can use to recreate this? I'm not sure if its causing any problems but would like to restore it to how it was possibly.
The samlcert alias is a self-signed certificate used for signing SAML requests to an external identity provider. Since it's self-signed, you can just use the 'Generate' operation from the machine endpoint of the Portal Admin API. I've attached the reference documentation plus a screenshot of the appropriate settings (just replace <FQDN> with your machine's fully-qualified domain name), that should put things back in place!
Generate a new certificate | Import a certificate into the portal | Portal for ArcGIS