How to solve dmxvalidatorerror

This is server action.


This is the query builder screen shot.
スクリーンショット 2020-09-09 21.04.15

<dmx-serverconnect id="serverconnect2" url="dmxConnect/api/Data/eventnamecheck.php" dmx-param:eventname="eventnameck.hidden2.value"></dmx-serverconnect>

here, I would like to check if eventname.value exists in the database already or not. if eventnameck.data.query==0, which means the same eventname as input’s eventname doesn’t exist in db.

Thank you.