Can you replicate the problem using the default Twenty Twelve theme with all plugins deactivated?
I am not a professional, so you are wanting me to deactivate my theme and plug-ins and install Twenty Twelve to see if this happens? Is there an easier way to do this? Code?
All WordPress sites should have a copy of the WordPress default theme (currently 2012) already installed. There is no magic bullet in these situations. This is just the start of basic troubleshooting and is a process of elimination deliberately designed to locate the root cause as quickly as possible by first removing the most obvious and common culprits via a series of (often) temporary steps.
There is no “code” solution until we know what the problem is.
I activated Twenty Twelve and disabled the plugins and it worked correctly. I am using Yoko theme.
What happens if you re-activate the Yoko theme but leave all plugins inactive?