robots.txt is unchanged after seting up this plugin

hi, I installed this plugin on my multisite network but no matter what I do, when I hit robots.txt in my browswer I see the default WordPress file. Any suggestions on what I should do?

https://www.ads-software.com/plugins/multisite-robotstxt-manager/

Web site here: https://p66new.test-wpmu.wexhosted.com/robots.txt