NAVIGATION ERROR – Next page url error

I am hoping someone can/will help me with this. All of the sudden (was not doing this before) whenever I use the next page navigation bar located at the bottom of the home page (or another) I get my default page cannot be found message? I’ve tried turning off the advanced navigation plugin but it continues to do the same thing. I’ve looked at the code but it is all Greek to me

Does anyone have any suggestions??