Hi @Anonymous ,
Do you mean that the submitted data from your canvas app could not be synced to your Excel table (hosted in your OneDrive folder)?
Based on the issue that you mentioned, I have made a test on my side, and don't have the issue that you mentioned. Please make sure the Excel table connection is valid in your canvas app. You could consider re-create a new connection to your Excel table from your app, then try your app again, check if the issue is solved.
Also please make sure these end users have enough permission to access your Excel table. And ask them do not open the Excel file in web browser when they want to submit data back to the Excel table.
Set the OnSuccess property of the Edit form to following:
Refresh('Excel Table');
Back()
when the Edit form data submitted successfully, the above OnSuccess Event would be fired, then your data source would be refreshed in your app.
Also please make sure the Network state in your end users' side is in good condition, the Network status would also affect the data submission in PowerApps app.
Best regards,