Yes. I can browse to the User Management service and all available methods on each server. I've also done a filesystem compare between the servers, and the only differences other than timestamp are web.config (use different database and app URL) and license files.
The User Management Service returns an HTTP 200. In fact, this is the response body that comes back from the service on the servers that fail to authenticate:
HTML Code:
<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<soap:Body>
<AuthenticateUserResponse xmlns="http://prezzatech.com/Checkbox/Services">
<AuthenticateUserResult xsi:nil="true" />
</AuthenticateUserResponse>
</soap:Body>
</soap:Envelope>
Even though the call completes and a nil is returned, there's no evidence that I can find of an exception being thrown. I am stumped at what I missed to cause this difference in behavior.