No doubt this has been mentioned and answered here. What would cause my P4P to lift off then not allow a forward or backward moment but does allow movement up, down and left and right? There was also beeping as though there are obstacles. Now here's the confusion. Two days earlier I was at this very same location documenting a construction site with earth movers as the objects being photographed. I lifted off from the same spot on the ground as two days before. The two earlier flights were perfect not a beep or glitch of any kind.
In looking around here for an answer, I just came across some comments about sunshine contributing to some unusual drone behavior. The third troubled flight was a very bright sunny morning. In attempting to troubleshoot this condition, upon returning home which was maybe two blocks away from the construction site, I sent the drone up from my driveway. No problems were presented. So much to learn, but so worth the effort. This flying camera is gaining many new friends with the beautiful quality of video and still images.
Thanks up front for any help with this question.

You want to get familiar with "Visual Navigation Settings"
This section in the app allows you to turn on/off all kinds of features.

There are three screens. The very first setting is Forward/Backward obstacle sensing.
These vision sensors often get destracted when facing the sun. It's not in general about a sunny day but if direct sun hits the sensors.
Obviously in your case the sun could have only been the reason in one direction.
But maybe there were other obstacles around?
Although it's mostly annoying, help in the beginning may be to switch on the radar chart.
It shows you graphically which obstacles are being sensed.

In midflight when sun hits the sensors usually the message pops up "return sticks to midpoint first"
Did you get one of these?

If you are not in a tight space and you have VLOS I suggest you switch obstacle sensing off.
A good idea if there is restricted space and no need for fast flying is to fly in 'Tripod Mode'
This slows all movements down by far and let's you get closer to obstacles (by pressing the C2 button=Narrow Sensing)

Eric13 Posted at 2018-5-24 08:55
You want to get familiar with "Visual Navigation Settings"
This section in the app allows you to turn on/off all kinds of features.

Eric thank you. I have turned off some settings but if I remember one of the obstacle warning settings warns something about losing control of the aircraft if turned off. I will double check this. The mystery is why didn't I experience this anomaly with the last flights two days ago? I did see the braking alert but not sure if it was also "return sticks to midpoint first". I'm usually keeping my eye on the aircraft and composing the shot. Hell, who has time to read. Just joking. Thanks.

Brent Turner Posted at 2018-5-24 09:37
Eric thank you. I have turned off some settings but if I remember one of the obstacle warning settings warns something about losing control of the aircraft if turned off. I will double check this. The mystery is why didn't I experience this anomaly with the last flights two days ago? I did see the braking alert but not sure if it was also "return sticks to midpoint first". I'm usually keeping my eye on the aircraft and composing the shot. Hell, who has time to read. Just joking. Thanks.

There is no way that the drone looses stability or control gets lost by deactivating theses sensors.
You get warnings upon deactivating most of the features since DJI thinks it's safer if everything is on.

A more important thing in a work environment may be the 'Downward Vision Positioning' (up to 10m only!) : These are ultrasonic sensors constantly scanning the ground. This provides extra stability in mid-air. It's espescially good help when GPS reception is not sufficient.

Eric13 Posted at 2018-5-24 09:51
There is no way that the drone looses stability or control gets lost by deactivating theses sensors.
You get warnings upon deactivating most of the features since DJI thinks it's safer if everything is on.

Eric, I just returned from the construction site for the second time today. It took off and again beeps, sticks could not move the craft forward or backward. This was good. So based on your advice, I switched off the sensors. You are the man. The craft flew like an eagle, the aircraft was liquid in the sky. Thank you very much. At first thought, I would have believed it was a software issue.

Brent Turner Posted at 2018-5-24 11:39
Eric, I just returned from the construction site for the second time today. I took off and again beeps, sticks could not move the craft forward or backward. This was good. So based on your advice, I switched off the sensors. You are the man. The craft flew like an eagle, the aircraft was liquid in the sky. Thank you very much. At first thought, I would have believed it was a software issue.

I'm very glad I could help!

Just another advice - sorry for so many at a time:
When you are on construction sites, avoid by any circumstances taking off from concret (it's steel enforced) or metal structures.
That can throw off your compass - most likely resulting in the drone switching into Atti mode.
And you don't want that in a tight environment, esp. when it's windy.

I always have an aluminum landing pad with me.
(Aluminum is non-magnetic so it won't interfere with the 2 compasses in the legs of your drone)

Another advantage is that a landing pad provides you with a flat service.
The low hanging camera can easily get obstructed, even by grass...

Happy Flying - and do some Atti mode flight training in wide open area - just in case :-)

Eric13 Posted at 2018-5-24 11:56
I'm very glad I could help!

Just another advice - sorry for so many at a time:

Eric, thank you for your time and trouble. Your additional tips are excellent. Have a good holiday weekend and be well.

Eric13 Posted at 2018-5-24 08:55
You want to get familiar with "Visual Navigation Settings"
This section in the app allows you to turn on/off all kinds of features.

"Obviously in your case the sun could have only been the reason in one direction"
I think in some rare situations it actually can cause problems in both directions by the direct sun for one and the shadow in the other direction. I have not experienced this myself but as you can see in second picture from this post it sense something from behind that only can be the shadow as nothing was up there.

Another thread regarding OA but more minded the radar part, this again has been enabled (at least on the +) but no way to kill the beeping or adjust volume for this separate.