Symptoms

While running AppDeployment on a SharePoint server to deploy the K2 for SharePoint 2013 app to the SharePoint environment, after establishing a database connection, a warning is thrown to the user saying that the OAuth High Trust Information could not be retrieved from the database.

 

Diagnoses

When hitting Ok on this warning, the App will still deploy to the web applications that were selected, however cannot establish a proper connection with K2. This warning indicates that the AppDeployment application failed to retrieve the OAuth High Trust Certificates from the K2 database as well as establish a proper Trust in SharePoint for the K2 for SharePoint application.
 

Resolution

There is a way to move the certs and establish the trust in SharePoint manually, however it can become a bit tricky.

First, you must move the K2 OAuth High Trust certificate from the K2 Server cert console to both SharePoint machines into the Trusted Root Authority, Personal and Intermediate Certification Authorities certificate folders for the computer account on each SharePoint machine in the farm, regardless of their role.

To create the trust with SharePoint, you can run the following PowerShell script:
HighTrustConfig-ForSingleApp.ps1
As seen here: https://msdn.microsoft.com/en-us/library/office/dn579380(v=office.15).aspx

After these items complete successfully, you can proceeded with adding the app to the site collection or subsite of your choice. Pending the fact that your SharePoint environment is set up properly for apps, the registration should complete successfully.