Hello,
We need FTP access to wp-content/plugins/et-core-plugin and access to wp-content/themes/xstore and to your error log file. We don’t need access to anything else on your server. So, create an account with limited access to these folders only.
Also, remove the token from XStore > Authorization APIs and generate it again, please.
We can’t check the issue in more detail on your site without this access.
Regards