Non-root user can't upload files in filezilla (SFTP)

Instead of:

sudo chmod -R 775 /var/www/

You could use these two commands to set appropriate file and folder permissions:

sudo find /var/www/[new directory]/ -type f -exec chmod 664 {} ; sudo find /var/www/[new directory]/ -type d -exec chmod 775 {} ;

And then try on with more restrictive permissions until you’re satisfied.

Give the directories you want them to write in the right permissions using chown/chmod.

Thanks for the anwser, now I’ve been looking around and used this to achieve my goal. Is this a correct solution?

1. Establish a [new directory] at /var/www
2. Change the directory owner and group:
3. sudo chown www-data:www-data /var/www/[new directory]
4. allow the group to write to the directory with appropriate permissions:
5. sudo chmod -R 775 /var/www
6. Add myself to the www-data group:
7. sudo usermod -a -G www-data [my username]