Steps to reproduce:

1. Establish working HTTP based Zabbix frontend authentication config

1. 1. (My existing config uses client certificates, HTTP auth, and pre-existing Zabbix internal accounts)
2. Configure LDAP Server (with JIT Provisioning) that can perform a successful login (test), with the same username format as is used in the working HTTP based authentication (i.e. the same value that gets set for the PHP_AUTH_USER variable)
   1. (I want to use an LDAP server for identity / access control instead of managing internal accounts)
3. Set the default authentication to LDAP instead of Internal
4. Attempt to use HTTP login form

Result:
Zabbix login page says the user doesn't exist or is temporarily blocked.
Expected:
Zabbix does an LDAP search of the user from the PHP_AUTH_USER variable, performs JIT provisioning, and logs in the user.