We have a provider hosted app that is generally working. <br/>
The environment is set up and prepared (client id, secret, registered). 
The remote site is set up as well. When I add an app package (.app) to the AppCatalog, then navigate to a site collection>Site Contents>add an app>My App, the event receiver on the remote site fires, the app installs correctly and is fully functional.

The issue begins when I try to deploy the app not manually, but by using the following Powershell cmdlets:

 $spapp=Import-SPAppPackage -Path C:\Users\Administrator\Downloads\app\Package.app -Site http://MyServer/sites/site1 -Source CorporateCatalog
 $ii=Install-SPApp -Web http://MyServer/sites/site1 -Identity $spapp

The deployment fails and the error says:<br/>
**The remote event receiver callout failed.
Details: Access denied. You do not have permission to perform this action or access this resource.**

From the ULS:
[![enter image description here][1]][1]



When I install manually - ULS (successful despite all the exceptions :/ )
[![enter image description here][2]][2]



In both cases I am using the same .app package. Issue occurs on 2013 and 2016. Obviously I have permissions to the remote event receiver because it is the same one I am using when deploying the app manually.

I run Powershell as Administrator. 
I have no option of changing anything in the app code since the installation is... well... working the usual user way via AppCatalog.

Any advice is very welcome.

 [1]: https://i.sstatic.net/y9rKU.png
 [2]: https://i.sstatic.net/EN2VZ.png