post-headline </h>1>

Hello
I am new to this forum, and also new in wordpress.
However, i have an issue with ATA and i can't fix it, and i searched everywhere..

My demo site (working in progress) is on localhost.
I use Ata 3.7.7 but i have a weird issue.
On postpage-title i have the syntax: </h>1> and i dont know where to fix it.

I attach a print screen.
Thank you in advance.