Change data folder on installing

Hi, i am new in this, i need to install nextcloud data folder on HDD, i do this:
the disk is formated in Ext 4

sudo mkdir -p /media/pi/Disco/data

sudo chown www-data:www-data /media/pi/Disco/data

sudo chmod 750 /media/pi/Disco/data

and then, in the browser(on installation page), go to the ip of the raspberry and change the data folder but the page says this:
it is not possible to create or write to the data directory /media/pi/Disco/data

how can help me?
sorry for my english, i am spanish, Thanks!