4:00 am ET is not suitable to schedule meetings
When planning a call between Eastern Time and Mountain Daylight Time, you need to consider time difference between these time zones. ET is 2 hours ahead of MDT.
It is currently 4:00 am in ET, which is not a suitable time to arrange a call or meeting with someone in MDT, since it is 2:00 am there, which not within the optimal time span between 7:00 am and 11:00 pm.
You could, however, schedule a call between 9:00 am and 1:00 am your time. This time span will be between 7:00 am and 11:00 pm in MDT.