Hi Sonia,
I think YMD format is a must (so, '2024-06-21') - but it seems you tried that.
But is this for a Longitudinal project? If so, have you tried prepending the event name, such as:
[enrollment_arm_1][date]='2024-06-21'
I tried this in a longitudinal project, and it filtered appropriately; but if I did not specify the event, then the dashboard showed as empty. Are you getting an empty result, or something wrong in some other way?
Good luck
Jeff