404 Error showing next to Home on post pages

Earlier today, my site was only showing light green background with no content. I connected with my host and after a couple of hours working on it we got it to show again…but it shows ‘Error404’ beside the home button below the menu bar. See https://wellnessconnection.ca/100days/category/wellness/8 and in Firefox the tab says “nothing found for https://wellnessconnection.ca/100days/category/wellness/8” This seems to be occurring only on the pages where lists of blog articles are listed. And seems to be fine as soon as you click to a blog post. For example the error occurs on
https://wellnessconnection.ca/100days/category/2 and on https://wellnessconnection.ca/100days/category/wellness/3 and on https://wellnessconnection.ca/100days/category/wellness/4 etc…

When you look at my site you will see it is set up a little unusual. I have actually installed DT twice, once at wellnessconnection.ca and once at wellnessconnection.ca/100days … the problem is only in the second one…and my hosting company says it is a software problem not a hosting problem.

Can you tell me what has gone wrong. It worked fine until today. And i didn’t change anything. Moreover, right now I am not even sure if I am seeing what others see, because my hosting company reset it to a default theme and then I reset it to DP, but I seem to see things in my cache even though I have tried to delete my cache and history.

Thanks for your help.