Login error on joomla 3.4.1

Question

I have problem with my Joomla 3.4.1. Login generally works fine, but sometimes when a user logs-out and want to login again, I get this strange error.

I don't even know what this is says :

The URL which im getting the error is : http://bajeman.com/login-form?task=user.login

And the error looks like this :

My language setting in Joomla :
Could be this cause of the problem ?
My language is persian and its not listed in content page

Answer 1

You can give the language manually in content page.

Goto backend -> Extension -> Language manager -> Content -> New -> Here you can set the valid title and language tag then click save.