Hello Abecerra,
Thank you for notifying us of this. There is a bug with certain apps that were saved in Web Authoring which cause this.
If you are able to open the same app with a different client, please let me know what the version is. You can find it on the same scrren you've got below. I see your screenshot with the error is version 2.0.590. It would be good to know the version of your clients that are able to open it, just to confirm.
Once open, you can fix the app by manually clicking the 'Refresh" button on each of your tables in the Data Sources panel.
Note, this must be done on the Windows store version of PowerApps, not in the web authoring site.