The problem - VPS will not allow the Maivc to descend until switched off, this can be intermittent or a constant problem, other related issue, auto landing initated at a ludicrous height when pulling down on the left sitck.

I know there is a very large thread already dedicated to the ongoing VPS issue some mavics are having. There have been discussions about it being a firmware problem or a hardware problem.  
here is the soloution and answer to the firmware/hardware question

- fully recalibrate the mavic including the IMU
- do a factory reset
- do a firmware refresh

If the problem still persists, you have to open a case as the "unit needs a repair service"

It's a hardware problem folks

Sorry for that. Everytime when initating the auto landing, and the drone will not descend? Is there tip shown on the camera view at that time? How about synchronizing the fly records, and telling me through PM your DJI GO Account? And then decide whether it needs repair.

How about manual Landings ?  

SectorDrone Posted at 2017-1-18 01:00
How about manual Landings ?

turning off the VPS solves the issue which means you can manually land the Mavic, but turning off VPS then means you can't use any of the smart modes like active track etc

DJI-Paladin Posted at 2017-1-18 00:51
Sorry for that. Everytime when initating the auto landing, and the drone will not descend? Is there tip shown on the camera view at that time? How about synchronizing the fly records, and telling me through PM your DJI GO Account? And then decide whether it needs repair.

Hey, thanks for trying to help, but in the main thread I've been doing much the same as you've asked here with DJI-Ken, The one last thing I'm trying this week is a firmware downgrade, but I know of one other user thats tried this and has reported back saying the VPS issue is still prevalent. I'll fly the Mavic this week on the older firmware and if the issue re-occurs I'll begin an RMA

iPurvis Posted at 2017-1-18 02:33
Hey, thanks for trying to help, but in the main thread I've been doing much the same as you've asked here with DJI-Ken, The one last thing I'm trying this week is a firmware downgrade, but I know of one other user thats tried this and has reported back saying the VPS issue is still prevalent. I'll fly the Mavic this week on the older firmware and if the issue re-occurs I'll begin an RMA

Ok, if this issue occurs, can send back to get checked in detail.

@purvis, I've tried upgrading, downgrading, restoring , calibrating , I even tried and Indian dance and nothing works. I still think it's software related because there are reports of people receiving there mavics yesterday that are having VPS issues. If it is hardware dji's repair shop is going to get very busy in the next month.

R&L Aerial  Posted at 2017-1-18 04:20
@purvis, I've tried upgrading, downgrading, restoring , calibrating , I even tried and Indian dance and nothing works. I still think it's software related because there are reports of people receiving there mavics yesterday that are having VPS issues. If it is hardware dji's repair shop is going to get very busy in the next month.

You could be right, I don't doubt it for a second.

There are reports of people having the problem form as far back as November and the problem getting worse over time. The real thing is, we just don't know what batch of Mavics people are receiving, in that, thier Mavics may have been built 2 months ago and for whatever reason they only just happened to get them now, Remember DJI were holding off on deliveries due to camera and gimbal issues back in October and November so who knows what hardware is in recently received Mavics.

I'm just reporting back what DJI have asked me to do and seemingly, there's no software fix due. If there were and DJI wanted to avoid a huge influx of Mavic repairs wouldn't they ask customers to hold on for new firmware or get the new firmware out sharpish?
I know you're running Litchi with no issues ATM, Others are suggesting faults when using Litchi and another user posted a video with no phone in the controller at all, again issues....

I never use Auto Landing... in my manual landings I never got a single issue .... should I try auto land to check it ?

Encountered the issue again this morning and turning off VPS solved it. However you won't have the option to auto land, and cos VPS is off, the drone won't exactly hover in place when landing so it's a little more challenging to land.
There was an instance when my drone went into "landing" mode at about 10m, and I tried letting it continue to do its thing. I can confirm that it will just slowly descend until it lands on hard ground and turns itself off after that, no matter the height.

Same issue with the phantom 4 Pro+

Same issue with my phantom 4 standard