Dear Isabel,
many thanks for your reply. So it does show the same behavior on iOS and Android devices and it applies to any kind of resource. If I try to open a file (PDF) in the Moodle Mobile app, it shows me "Error while downloading content". And it does not download any data - regardless of being logged in as a student or administrator.
Do you have any ideas where to best start the troubleshooting? Or what could possibly cause this behavior?
As I am able to log in to the Moodle Mobile app, it seems that server connections to our Moodle server are possible from the Moodle Mobile app.
Thanks!