How can I resolve an 'Add Event' error in Facebook Pixel?

Hi,

Please help to show me how to solve a error while Im setting up a Facebook Pixel. I followed steps as instruction video but the error happened, I dont know which step I did wrong. After setting, I still can not do “Add Event” the screen shows as below. I also checked the ID of Business Manager ID and Ad Account and Pixel ID are match as instructed on community. Thank you!!

Regards,

Carol.