Steps to reproduce:

1. Open Users > Authentication
2. Enable SAML authentication and save following configuration:
   1. SSO service URL: test.com
   2. Encrypt > Name: checked
3. Observe: saved without errors
4. Try to open login page index_sso.php when logged out

Result:
Error is displayed related to wrong configuration

Expected:
URL - either increase constrain for inline validation or alter checkIdPSettings and logic to support urls without http(s) at start.

For other validation depends on server settings and can't be modified in form so that values are valid. I would say that here would good logic would be to at least display error message if user tries to save it as enabled.

API validation should also be extended probably.