Sorry Salvatore, the services server is shut-down permanently
since May 19th. There is no alternative way to build apps that run in the background using App Inventor 2. The services site is not available any more. If you saved an aia of your Project, you can re-build it on the main server but without background capabilities.
The above notice has been posting on the site for over a year.
To build a service app, consider the professional Android Studio, B4A or Delphi Community Edition compilers. All are free and buld service apps.
Regards,
Steve