EKF Problems , always make plane unstable


I used to fly my plane very good in manual but when I change to any mode with controls such as ( FBWA - Auto ) some times it show me warning in the HUD such as

Error compass variance
Error ver position variance
Error Velocity

and EKF status change to Red color
and plane start to behave wrong and unstable , radio control command tot response as expected , or plane go away from the path in auto mode .

what is the EKF problems that effect the controls ?

any information may help , I need to understand many thing in EKF

I am using vm: AP 3.7.1

I have other questions about EKF will post it later


That’s related to compass and GPS. Do you have them attached? Is compass calibrated?

yes , I have GPS and the compass is attached within the Pixhawk , and calibrated