Motors not Arming

[countryal]

Was flying my P4 today and the motors quit arming. Was using Litchi. Also noticed auto take off wouldn't work at times. I figured out the problem. I have Bahia grass in my yard and some of the grass stems were tall enough for the obstacle avoidance to detect and the motors and auto take off won't work if that happens. Just thought I would mention this in case anyone else has a motor arming problem. I'll be cutting the grass tomorrow!