Hi RissaG80:
As I have known, because I contacted the support of the theme, there is a problem with the Advanced Custom Fields – Widget Relationship Field add-on. You must disable and erase it, and then install this one:
https://bitbucket.org/ajgagnon/widget-relationship-field-add-on-for-advanced-custom-fields/get/a5a0a4c9a689.zip
Then, will work.
Good luck!