Restrict Scheduling Alert while scheduling multiple appointments for same time for same day

Need to avoid the scheduling alert which shows up when you try to schedule multiple appointments on the same time for same day. We can always Ignore and Save but need to restrict this pop up overall. Please refer below screenshot. I have tried to change the user working hours to all day without any breaks and increase the capacity in user working hours as suggested here(https://www.inogic.com/blog/2015/12/scheduling-multiple-appointments-for-the-same-time-and-same-person/) but this is not working for me. Any suggestions?