Hi @Dayananthan ,
Could you please share a bit more about your scenario?
Do you mean that only one of your end users could not write data back to data source?
Which data source do you want the data to be written back to?
Currently, I could not reproduce your issue on my side. Please check if the user (this issue related to) has enough permission to access the data source which the embedded canvas app writes data back to.
If you want the user to be able to write data back to corresponding data source using canvas app, you need also to share the corresponding data source to the end user.
More details about sharing app resource, please check the following article:
https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/share-app-resources
In addition, please also consider re-share your canvas app, data source and your Power BI report with the end user, then check if the issue is solved.
Best regards,