Hello Daniel,
Thank you for reaching out to the Microsoft Community! I’m truly sorry to learn that you’re experiencing issues with your OneDrive. Thanks for the detailed report. Based on your issue with OneDrive for Android not backing up your gallery since September 1st, and the error message “Item cannot be displayed. Check your network connection…”, This issue seems to be affecting Samsung Galaxy S23 users running Android 15 / One UI 7.0, especially after recent updates. The error and backup failure may be due to A sync conflict between Samsung Gallery and OneDrive or corrupted cache/data or app permissions not fully resetting after reinstall or Account linking issues between Samsung and Microsoft accounts and a bug in OneDrive version 7.38 affecting gallery sync.
You can do is use the OneDrive Web App. Log in at onedrive.live.com to confirm if files are visible there. Sometimes the mobile app fails to display items that are actually uploaded. And Try Manual Upload, Open your Gallery or Files app then select recent photos and use Share > OneDrive to manually upload
Reference link
Feel free to reply for better understanding.
Warm regards,
JayMark