Planning : Overlapping tasks

Hello,

We have a problem with GLPI. We have implemented the scheduled task system for technicians, however when the same technician schedules the task for a day and a time when there is already another task with the same time on the same day, it just marks him a message of 'Warning:

"User ******* is busy for the selected time period

• Task ticket for one: from 02-17-2021 10:30 am to 02-17-2021 11:00 am
  New Agent Form
• External event: from 02-17-2021 10:00 to 02-17-2021 12:00
  busy "

We want this to block the user and not save the task.

Looking forward to your feedback,

Thank you very much.

Regards,