Symptoms

The "Value is out of range (1..1000)" pop-up is received when trying to set the Maximum length value to more than 1000 in the field's validation settings:

Cause

The FlexiCapture 12 does not permit the capture and storing of Data over 1000 characters using Auto Validation rules.

Resolution

Set the Maximum length value to 1000 or less. The limitations are only applied to the Validation rules. 
The field itself can contain more than 1000 characters in one text field if needed.

Additional information

How many characters can be stored in a Text field?