Invalid JSON response

Hi im getting this error on vendors page from admin dashboard

DataTables warning: table id=wcfm-vendors – Invalid JSON response. For more information about this error, please see https://datatables.net/tn/1

Hello Please help I’m running WCFM Multivendor marketplace plugin and from vendor dashboard they get the following error “DataTables warning: table id=wcfm-enquiry – Invalid JSON response. For more information about this error, please see https://datatables.net/tn/1”

Everything works fine but that option, customers can ask questions in that inquiry tab from single product page, but vendors when checking the inquiry board in when they get said error

Any help or guidance would be helpful Thanks