Multisite Install on a subdomain

So I want to install a multisite WP on a subdomain using subdirectories. So itd be like mysite.example.com/site1. I tried to do this already and would always run into 404 errors while using subdirectories, and after trying to use subdomains (site1.mysite.example.com) I would just get redirected to the main site (example.com) while it would say its the subdomain. Any help would be greatly appreciated! And yes, i already made sure mod_rewrite, and htacces are configured correctly.