Hi there I bought a  second hand P4P Plus last week.
I have cleared the cache in the controller, logged in to my own account, changed the name of the drone on the Controller, refreshed all firmware using DJI Assistant, reset the controller to factory defaults, etc etc
The machine flies fine and records flights but wont sync them - just get a message saying that the sync failed.
I have downloaded the flight files off the drone itself and can save them in Airdata but the automatic syncing function is not available as the flight records are not syncing to the DJI Servers,
It is my suspicion that the cause is that the drone was activated under a different account.  
What can I do to get round this?
Des

It is my suspicion that the cause is that the drone was activated under a different account.  

That won't prevent you using the drone and synching the flight records to your account.
The cause will be something else.

Hello there Des. I am sorry for the trouble this has caused and thank you for reaching out. Can you please check whether all flight records fail to be synchronized? If the issue persists, please try to change the network or make sure you have a good internet connection for us to be able to isolate the said issue. Please keep us posted for further assistance. Thank you.

DJI Stephen Posted at 2021-12-12 20:15
Hello there Des. I am sorry for the trouble this has caused and thank you for reaching out. Can you please check whether all flight records fail to be synchronized? If the issue persists, please try to change the network or make sure you have a good internet connection for us to be able to isolate the said issue. Please keep us posted for further assistance. Thank you.

Hi there this flight syncing  is still a problem and I have now found that the Unlocking List wont refresh either (and I have a job at Manchester FRZ tomorrow - I have an unlock code but it wont load up to the controller).  Also the controller (GL300E) wont check for updates.  These issues must all be related somehow

Air2Ground Posted at 2-15 12:31
Hi there this flight syncing  is still a problem and I have now found that the Unlocking List wont refresh either (and I have a job at Manchester FRZ tomorrow - I have an unlock code but it wont load up to the controller).  Also the controller (GL300E) wont check for updates.  These issues must all be related somehow

Sorted at last.  The controller software was out of date - it wasn't checking for itself, but I noticed a small window below the pull down menu at the top asking me if I wanted to update to a newer version.  I did, it updated, adn now the Controller syncs my flights and I can see teh unlock code I have been sent.  Happy days