-go to WPML > Theme and plugins localization
-tick 'Use theme or plugin text domains when gettext calls do not use a string literal'
-click 'Save' button
-select your theme (rockon)
-click 'Scan selected themes for strings'
-go to WPML > String Translation and search that string. It should be under 'default' text domain'
-translate the string completely and save.
Also, I would like to recommend you to increase your max input vars, currently it has a value of 1000 in your WordPress Dashboard > WPML > Support section.
Please, try to increase it to 5000. You might need some assistance from your host to properly set this up.