Symptoms

We are unable to install K2 application for SharePoint (see attachment)

K2 app was deployed successfully on the app catalog. (from 4.4120.5.1 to 4.4120.8.1, see attachment)

K2 app was registered successfully on the app catalog.

Yet when we try to activate the sitecollection, we get the following error during page "Manage App Activation":
Site collection must be located in the same web application as the app catalog
 

Diagnoses

The issue certainly comes from the App catalog has his own Hostname : http://store-klif.xxxxx.corp.priv
The web application url not start like the app catalog: http://host-klif.portal.xxxxx.corp.priv

 

Resolution

In Part "Manage App Deployments (Sharepoint)", we selected "All Paths" but not any "Site collection".
We activated the K2 application from the target Site Collection (not from the "Manage App Activation"): From the Site collection: "Site Contents"/"K2 blackpearl for Sharepoint"/"Activate Site Collection"

Note: we played too with the Sharepoint Timerjob.