SSL For SAAS: Wildcard Errors

I’m trying to create a couple of custom hostnames within SSL for SAAS, when entering “*”, I receive the following error:
“Hostname should not include wildcard. Please use ‘wildcard’ boolean field to cover wildcard domain. (Code: 1453)”

When checking the docs and searching around, I can’t find any reference to error code 1453:

Any clue what “‘wildcard’ boolean field” is meant to be? There’s no checkbox or anything that I can tick.

Screenshot attached in case it helps

" Wildcard Custom Hostnames
Extend encryption, performance, and security to any customer subdomain with wildcard custom hostnames."

Is this enterprise only?

Ah just saw wildcard is indeed enterprise only, shame