Plugin not working under subfolder

Hi,

Currently I have one website in my main folder httpdocs/, let’s say it’s site1.com, I installed a new wordpress webisite under that folder so it is a subfolder(httpdocs/site2) of the main website, if I turn on the plugin and set the wp-admin login link(example. http://www.site1.com/site2/customadminlogin), try to access it, it redirects me to the 404 of the parent(main) website (www.site1.com/site2/404, the layout is from the site1 404 page).

If I turn of the plugin I can access admin dashboard with /wp-admin/.

Please let me know if you have any fixes for this.

Thanks