Hello, I created this Validation Rule, however, it does not execute properly when I save a record.

The idea is when "In Negotiations" is "No" and the field "Description of Negotiation" is left blank and user tries to save the record, the user should be prompted to fill in the "Description of Negotiation" field, however, this is not executing correctly.

Any ideas?

Thanks!

AND(
ISPICKVAL(In_Negotiations__c, "No"),
ISNULL(Description_of_Negotiation__c))