Category Link Error in Navigation Menu

I’m currently discovering some issues with the pages in my navigation menu. Essentially, they’re not directing to their proper category (Category being their navigation page), and instead is displaying an Error 404.

I noticed that this happened after I integrated a big cartel store. It somehow changed my permalinks for each of those pages. Can anyone help me figure how my pages can be successfully re-routed back it’s proper category page?

The website url is below. Notice that my first and second posts should be routing to the about and events page, respectively.

http://www.thesiegesound.com