I am trying to build a Validation Rule that if our opportunity stage is Closed Won, Closed Lost, No Decision, that the custom resolution feilds we created for resolution need to be filled out. I read some old forms and I was told to use a formula like this, but it does not seem to be working. Is there something I am doing wrong?
Thanks in advance

AND ( 
TEXT(StageName) = "Closed Won,Closed Lost,No Decision", 
ISBLANK( Resolution_Date__c ))

I am trying to build a Validation Rule that if our opportunity stage is Closed Won, Closed Lost, No Decision, that the custom resolution feilds we created for resolution need to be filled out. I read some old forms and I was told to use a formula like this, but it does not seem to be working. Is there something I am doing wrong?
Thanks in advance

AND ( 
TEXT(StageName) = "Closed Won,Closed Lost,No Decision", 
ISBLANK( Resolution_Date__c ))