First, Sorry to @Andrew Nevins and @esmi was to hurry for help! my fault! :)
Ok, I get this bug to day after upgrading WP core from 3.8.3 to 3.9, where I use the multisite mode with P2 v1.5.3. Also for my installation I use this plugin to set the https.
Reading from the web many people recommend to reflush permalinks changing back to default and then again to post name, tried without a succes.
Also think could be a browser problem, but try with Firefox, Chrome and Safari (all in OSX), again... nothing change.
Most of the people have problems with the reply but in my case is just when I try to create a new post from home, frontend.
Thanx for any help.