Alright I tested some more. The goal of the test is to login at start of screen, and upon login successful: post message. Here are the results.
- The example app works, no error, no warnings, posts perfectly from any FB account
- The example app shuts down without any error message when/after you do something with asking for permissions
- However, when the extension is linked to the Facebook ID of my app, it no longer works
- And vice versa when I use the Facebook ID of the example in my own app, it does work. Therefore I am certain the events and settings in the project are fine, but it's something in the Facebook app settings.
My app will post when I use it logged in on the account of the developer (left). The warning says that some permissions need to be approved by review. It's true, because when someone else (who isn't in the developer team) logs in and uses my app it doesn't show this warning but also does not implement the permission and therefore does not post.
And this approval screen I get when I use the example app, or I use my own app from the developer facebook account. After approval, the app will post messages without a problem.
In the app settings you can see that the permission to post to wall is missing with my app and it's there in the settings of the example project.
This advice I've seen a lot when I looked up this problem. It looks like facebook permission publish_actions is required to let an app post to a wall of someone other than the app developer. More info on that is found in this doc on Facebook here.