Hello,

Your parent theme is 3.3.1 http://prntscr.com/kkqsr6 The recent version is 4.3 please upgrade your theme.

Next, deactivate all the third parties plugins not related to the theme and check the issue.

In order to distinguish which plugins relate to the theme and which do not, deactivate them all and then navigate to Appearance > Install plugins and activate all in the list.

Then, activate your plugins one by one checking which one causes the problem.

Best Regards