The Computer has connection with emonth but it doesn´t save the measures

Good morning, I have an emonth net connected to a PC, it has been recording measures without problem for months and its measures has been saving in the PC.

But a month ago, the measures stopped saving in the PC but in the computer appears the emonth net connected, I attached the information in the webside.

But when I download the information as I have done other months the columns of temperatures appears blank.

The font label says that it is connected and all the devices.

I have two question.

  1.   Has the emonpi an inner memory?
    
  2.   Where are the information saved?
    

Upgrade information.

This afternoon I reset the emonpi device and then it started record again, but the measures that disappeared from November to December keep disappeared, otherwise, the rest of months before the moment that the device stopped appeared.

Why the device stopped working? It is possible to get the disappeared measures?

Thanks for your help.