From the front end when i want to browse the server for inserting an image or video i got : "unable to connect to the back end". the same error appears in back end (k2 media manager). there is no error in joomla media manager, only K2.

To finish easy image gallery component seems buggy :

Thanks for any help

Hi. Probably some other extension is breaking the JSON request. Please try to :
1. Turn error reporting to "None" under Joomla! configuration
2. Try to disable some system plugins that may cause the issue.