No. ProBackup can only back up accounts on smartsheet.com.
Smartsheet Regions Europe (smartsheet.eu), Smartsheet Regions Australia (smartsheet.au) and Smartsheet Gov (smartsheetgov.com) are separate Smartsheet instances with their own logins. ProBackup does not support them.
You can tell which instance you use from the address in your browser when you are signed in to Smartsheet: app.smartsheet.com is supported, app.smartsheet.eu and app.smartsheet.au are not.