Unchecking DNS on the MTA tab results in

zimbra JavaScript error encountered in method ZaXFormViewController.prototype.runValidationStack

message: E[C] has no properties fileName: https://172.16.0.10:7071/zimbraAdmin...v=080522114104 lineNumber: 6153 stack: (undefined)@https://172.16.0.10:7071/zimbraAdmin/js/Admin_all.js.zgz?v=080522114104:6153 call([object Object],undefined)@:0 (undefined)@https://172.16.0.10:7071/z...

I have done
zmcontrol stop
rm -rf /opt/zimbra/jetty/work/*
cleared browser cache
and retried but I received the same error.

I have a work around in place but what does this error mean?