Server2012R2 Domain Computer not recognizing Admin Credentials?

I am thinking that there is a security setting causing my problem.

Set up a new domain (someone else did it).  Joined a single computer to the domain.  It is a new computer running Win8.1 Pro.  Very small network. 10 users.  Logged into the computer with a domain user account. If I try to install a new program or even update a program that requires elevated admin privileges, it prompts me for the new credentials.  When I enter them it acts as if they are incorrect.  It just keeps prompting me to supply the credentials.  If I log the domain user account off and log back in with the domain admin account (the same one that wouldn't work before) it accepts them and completes the install.

I also have a QNAP TVS-663 NAS in the network.  I believe that I have it setup properly for Active Directory authentication.  The shares are showing up on the network from the domain computer but the same thing is happening - It prompts for credentials and if I use the domain user or the domain admin or the local admin for the NAS crediential it will not connect.  It just keeps prompting for new credentials.

I am sure it is a setting that I have wrong, but cannot find it.

Thanks.