Can't view posts ("Page can't be found")

I’ve spent the last hour or so combing through the internet and I haven’t been able to find a solution to this problem.

So I’ve installed multisite and I’ve setup my first site. The network is using subdomains. I also installed the WordPress MU Domain Mapping plugin.

Subdomain: shadowhunters.7thpage.com (7thpage.com, main site)
Domain: shadowhuntershq.net

Thus far, the site is accessible via both the subdomain and domain. I can access everything in the Dashboard, so it all seems to be running well. However, I run into a problem when I try to view the posts. If you go to the site, you’ll see that there are two posts. If you try to view the comments or go to the page where the post is located, you get an error, “Page can’t be found.”

I’m not sure what is causing this and I don’t know how to fix it. I should add that it appears that I can successfully access the pages (ex: https://shadowhuntershq.net/sample-page/)

Anyone know how to fix this?

I don’t know if the following is relevant, but I figure I’ll post it just in case:
– I’m using cPanel
– Shadowhuntershq.net is listed as an addon domain and points to the directory where 7thpage.com is located

Thanks in advance!