Hi Frits,
To troubleshoot the issue you encountered, I’d like to collect some information.
1. You mentioned “At a clients office the desktop app is working for some minutes and then it won´t work anymore”, do you mean all Outlook desktops in their organization encounter the issue?
2. What’s the symptom of Outlook when “it won’t work anymore”?
3. When you said “Outlook is constantly disconnected”, do you mean the connection status in the bottom of Outlook is disconnected?
4. As for the problem of OWA app on your iPad, does it exist if you set up your Office 365 account on other iPads? How did you set up the account in the iPad? Detailed steps will be appreciated.
Thanks,
David Zhang