trying to complete - Enhance Agentforce to Act on Data with Conversational Language

When on  

1. Click the Event Summary element.
2. For Value, copy and paste this: 
   Check-in date of {!Reservation_1.Check_in_Date_c__c}, check-out date of {!Reservation_1.Check_out_Date_c__c}, for room type {!Reservation_1.Room_type_c__c}.

3. Click outside the Value box so the Save button becomes available, then click Save.
4. Click Activate.
5. Close the Flow tab. 
    
    

Doing this exactly as prescribed but getting error message:  

The "Reservation_1.Check_in_Date_c__c" resource can't be used as a merge field.

How do I get past this?

#Trailhead Challenges