Sometimes when you click a link to a file or folder that someone shared with you, the OneDrive app asks you to open the link in your web browser instead of the app. This happens when we need more information from Office 365 to ensure that the link is secure. Here are some situations where you may be asked to open a link in your mobile web browser instead of the OneDrive mobile app:
You're opening a link to a file or folder from a different company.
Someone sent you a link without giving you permission to open it.
You're clicking an older link that doesn't open in a mobile app.
We always keep your files secure whether the link opens in the OneDrive mobile app or the web browser. When you share files and folders, you can control who has access.