If the beep codes are the same on the C23/E90 as for the CGO series you have a Pitch encoder fault. [
As
@DoomMeister said, you have a Pitch encoder error. The encoder is a small board just under the right hand camera hub cap. That's
DRONE right, as in the passenger side of your car (for folks that drive on the right hand side of the road).
Most common causes of this failure are:
1.)
Bad sensor board. It happens, but it is fairly rare.
2.)
Damaged pitch ribbon. Only common if the drone has been in a hard landing, or transported without the gimbal lock in place.
3.)
Bad sensor magnet. This one is only recently recognized, and not well understood. It can be characterized by symptoms as slight as the magnet appears normal, but has lost most or ALL of it's magnetism. In most observed instances, the magnet is covered by a fuzzy material resembling iron dust, but of a lighter color. The chrome plating is often flaking off the magnet. The magnet is often in a state of physically crumbling for no apparent reason. Instances have been observed from Florida, Kansas, Massachusetts and California, so it does not appear to be a regional environmental issue. It does NOT seem related to operating in dusty conditions. Only one instance showed any sign of dust anywhere else in the encoder area or anywhere else on the camera.
4.)
Firmware Glitch. I have only seen this one twice. The resolution was to downgrade the gimbal firmware to original Build 652, then upgrade to Build 784, and then return to your normal build. This one is obviously also not well understood (at least by me). And not very likely to yield results, but seemed worth mentioning.
5.)
Gimbal Board Failure: I have not yet seen a spontaneous gimbal board failure. All were related to crash events or reverse power events. But, of course, always remains a possibility.
Lots of possibilities. As
@DoomMeister also mentioned, any history you can provide might help one of the possibilities to stand out, and possibly help us recommend a more specific resolution.