tonite flight of DHL445 from san juan (TJSJ) makes u-turn back to san juan , it,s desitination was wilmington ohio (KILN) …SORRY I,M NEW HERE DON,T KNOW HOW TO BRING -UP-LINK ,HOW DO WE FIND OUT WHY IT WAS DEVIATED ??? 
Almost definitely mechanical. Reasons for diversions are not reported unless there is an incident which results in damage or injury. Occasionally with passenger flights there’s a new story about unusual diversions, but this one is neither a passenger flight nor unusual (presumably).
Mark,
Why does the map display the prior flight on the above link from the history portion?
The map being displayed here is map3.flightaware.com/flight_trac … 1200972660 when I click the above link.
The map displayed in your link above is the flight flightaware.com/live/flight/DHL4 … /TJSJ/TJSJ flight
I would have thought it would display the same map as map7.flightaware.com/flight_trac … 1200993960 map?
I was working from the history link of flightaware.com/live/flight/DHL445/history to get the inconsistency of map displays
MSIE 6.0 is the browser flavor of choice at my work.
Allen
EDIT COMPLETED map properties updated
Because the most recent flight has no departure time; it’s a known bug.