EOC - group members do not successfully authenticate - what is OrionWeb

I've added a Windows security group to EOC.

However, group members do not authenticate - they get a username/login screen when attempting to access EOC.

I see some troubleshooting articles such as: https://support.solarwinds.com/SuccessCenter/s/article/Active-Directory-group-members-unable-to-login?language=en_US

The above article contains a reference to "OrionWeb" - "AD group account logins return an invalid username or password and OrionWeb shows errors such as.." 

I would like to dig deeper for troubleshooting. But... not sure what is "OrionWeb" and how do I access that resource?

Thanks in advance for any guidance.