This article was created in response to a support issue logged with K2. The content may include typographical errors and may be revised at any time without notice This article is not considered official documentation for K2 software and is provided "as is" with no warranties.
When loading the "Manage App Activation" page for the default K2 Server, an empty list is rendered.
This occurs when there are multiple K2 Servers registered in the same SharePoint Online environment.
You can confirm this by looking at the K2S Tracking hidden list which can be accessed by navigating to: https://[App Catalog Site URL]/Lists/K2S Tracking. In this list there should be multiple K2 Server entries (e.g., Development, Production, etc)
On the first load if the default environment is selected, the UI screen doesn't seem to recognize the default server and doesn't bring back any of the site collections that have been previously activated.
This is a known issue in K2. It has been addressed in K2 5.2 OnPrem and K2 Cloud Update 5.
As a workaround, you have to go in, change servers and select the secondary K2 Server URL.
Then change servers again, and select the default K2 server the second time in order for it to show the list of activated sites for the default K2 Server.