Multisite adds /blog in the URL

After I installed the multisite, the URL adds a /blog in the permalinks.
A few infos in the internet said that I can remove that in the main site just by changing the configs in the Sites>>MainSite>>Config. and not making any more changes to the permalinks page.

I did that and the URL is now OK, but after I installed the fundraising plugin, the projects created are listed in the http://mydomain.com/blog/projects. But if i go to the page i get a 404 error.

How can I fix this issue. Either removing the /blog from the URL in another way, or fixing the fundrasing plugin URL.