Should the wifi signal strength in the garage be low, you will want to boost the signal if possible, such as moving the wifi router closer to the garage. Does this fix the issue?
Otherwise, in this scenario you will want to remove and re add the MyQ device from Alarm.com. Removing the gateway is something only your dealer can do at this time. Would you like for me to remove that device?
Keep in mind these commands can only be performed during normal business hours.