The authentication error is misleading when enabling LDAP authentication

Steps to reproduce:

1. Enable LDAP authentication
2. Use dummy string for all of the fields (e.g. "LDAP host: abc")
3. Click "Test"

Result:
The "Login name or password is incorrect!" error. At the same time, I can see a correct error message in the "Details" (see screenshot)

Expected:
Zabbix displays correct error message (i.e. "Can't contact LDAP server" instead of "Login name or password is incorrect!")