Parameter value in Data Factory Triggered pipeline

I have a pipeline configured in azure data factory which basically does create a backup file (JSON) from a cosmosDB dataset and it's saved in a blob storage, my problem comes when I want to schedule the copy task in a trigger, I see that I have to specify the value for windowStart (parameter already defined to name the JSON file with the date of the execution. ) as shown below: Destination path: And as you can see when I want to trigger it does ask me to specify the value for windowStart. I tried below functions to specify that with no success so far: "@{pipeline().parameters.windowStart}" "@{formatDateTime(pipeline().startTime,'o')" "@{formatDateTime(utcnow(),'yyyy-MM-dd')}" "@{formatDateTime(trigger().startTime,'yyyy-MM-dd')}" And the error I always get is as shown below: Have anyone any idea or way to fix that, or have someone faced the same issue before ?