Why am I unable to open a document in OneDrive Online?

1. Check if a recent update is available for OneDrive.
2. Ensure that the document you are trying to open is stored in OneDrive.
3. Make sure that your internet connection is stable.
4. If you are accessing an online document, make sure that the document is not already open in another browser window or app.
5. Check that the file size does not exceed the maximum file size.