"Invalid or Unsupported Image File" when trying to open tiff in AutoCad 2017

I am trying to open .tiff orthos created with Pix4D in AutoCad 2017. When I drag and drop, I have an "invalid or unsupported imgae file" message. I followed the webinar (Create new layer, double click on it, drag and drop). Clients are getting anxious because they are not being able to work.