Okay, it's a little hard to be sure with the obfuscation (and I understand why you did that), so here's a guide to how those fields should be populated from my lab:
Alias: This doesn't matter, it's just for human readability.
Domain Name: The FQDN of your domain, so you'll need to include the .com or .local or whatever on the domain.
Directory Service Server: This needs to be the hostname or IP of a domain controller.
User Name: The user that has rights to do directory queries. Basically, any user has this right, so this account doesn't need to be special.
Note: The LEM will put the username provided together with the domain name, so you don't want to put the domain in the User Name field.
Password: For the use doing the queries.
Encryption: This depends on your environment.
Custom Port: Unless you know you've changed the AD ports on your DCs, leave this blank. LEM will assume the defaults.
Test Domain Name: The FQDN of your domain controller.
Make sure the connector is saved and running before clicking the "Test Domain Connection" button, or it will not work.
Now that you've done all that, though, this connector is just for pulling AD information (assuming you're running a newer version of LEM) like groups. If you want authentication to work, you'll need to check out these steps:
Set up Active Directory authentication in LEM - SolarWinds Worldwide, LLC. Help and Support