We tried to install Travel Request System from SharePoint online store, but it fails with "You can't add this app here."
If we click Find out why, we get the message "Sorry, this app is not supported on your server"
We asked provider and only requirement is that we have workflow enabled, which it is. My account is global admin and I can install other apps fine.
can any of you confirm if you manage to install this app? If so what other site features are enabled?