Error 500 grav upgrade

we are trying to develop a website using grav http://www.enersport.it/test/ (first time) we are stuck because everytime we try to upgrade grav from admin we get error 500 website is currently down and we are not sure why, can you help us?

Have you looked at the troubleshooting docs?

If you get a 500 error installing from Admin, try updating Grav from the command line (bin/gpm selfupgrade)