Hiding Primary Domain while on Sub Domain

Hi all,

I can not find an answer to this, or don’t know what to look for.

I operate lets say https://www.mysite.com and it is used as a primary domain.

I then host multiple different sites under subdomains ie. https://www.mysite.com/sub.

Now 3 of the 4 sites do what I want and display their urls as https://www.thissite.com no matter where I am on the site.

But one of them does this. I go to the site https://www.problemsite.com. It goes perfect and the url is correct up top. But once I click a link to a new page on the site it re-directs it to https://www.mysite.com/problemsite/page=id

Any ideas on how to fix that??

Its not a deal breaker, I just don’t want to primary domain to show in the url.

Thanks in advance ??