error 400 on working website !!

So i have error 400 when i click the buttons on my website please check it out here when i click the buutton it takes me to . right link then on the second link when i click button it doesnt work pls help me thanks

Make sure the link exists. Looks like it takes you to a 404 error.

your code
<h2> To go to the home page click here --> <a href=""> HERE GUYS ;) </a> </h2></center>

you must use http/s for absolute path

<a href="">

on homepage you have letter “s” outside of div

use button not “form submit” if you just want link to index2.html

as @EasyHost said that page / file does not exist

and <title>YoYo'</title>
go inside of <head>