After updating Nintex Forms for SharePoint 2013 to version 184.108.40.206/220.127.116.11, the following error might occur in any form rule that has both Lookup() function and IsNullOrEmpty() function together:
There was an issue validating the data entered on the form: please try again. If the problem persists, contact the form designer.
- Create new form variable, in the formula add the whole rule to that variable. For example:
- Create new validation rule on the form, where you evaluate the form variable based if it is true or false.