"Add Tab" Home Screen not working

Hi All,

In Home Screen under Action–> Add Tab , getting a popup and after entering the details just page is refreshing but new Tab is not adding .

** config_override i had changed permission to 0775 – based on old threads.

** My Suite version : Version 7.9.5 – Sugar Version 6.5.24 (Build 509)

Please let me know how to resolve this