The requested page ___ could not be found

Hi there. Some background. I have some very rudimentary wordpress skills and my html skills are near non-existent.

I’m working on converting a Bluehost hosted drupal website to wordpress. Bluehost told me that I could install wordpress on a subfolder we’ll call mainsite/sub1 and work on that until I was ready to replace the WP site with the drupal site. That seemed to work fine.

I had done a bunch of work on the wp site and then went away for the weekend. Coming back all of the pages that weren’t my main page started to give me “Page Not Found The requested page mainsite/sub1/about-us could not be found” under the mainsite address. That was the same for all the other non-Home pages as well. Hmm. I tried disabling all the plugins but that didn’t help. Contacted Bluehost to see if they could help me and all that they could tell me was that something got deleted that I needed for the pages to show. Mostly I was confused and the rep didn’t seem too helpful and I had no idea how to fix the problem on my own. In the end I shrugged and set up another wp site in another subfolder mainsite/sub2.

Did a bunch of work on it and then was checking through the pages to see if everything was showing as I wanted. Got to the Contact page and saw I forgot to set up “Fast Secure Contact Form” plugin. I log into the mainsite/sub1 page to see what my settings were. Save changes go to check Contact page and blam “Page Not Found The requested page mainsite/sub1/contact could not be found”. Again rest of pages except home page show same error. One of my theories after the sub1 failure was that something in iThemes Security had messed something up so I was waiting before activating that but I guess that wasn’t it.

I have no idea whether this is a hosting issue, wp issue, or something else. Any help would be greatly appreciated.