I've been checking on and off for a few weeks now and the offline logo seems to be always there. Is the program over? Is there another website that shows current views? Thanks for your time!
As of 08/25/2019, according to the NASA HDEV page:
The High Definition Earth-Viewing (HDEV) experiment on the International Space Station has experienced a loss of data, and ground computers are no longer receiving communications from the payload. A team of engineers are reviewing the available health and status information from HDEV to identify what may have occurred. Additional updates will be published as they become available.
The link to the HDEV page that David Ratti gives does not give any updates further that what he mentions. However, the wikipedia page for HDEV has more information (that I cannot find a source for)
Failure of the cameras (Update August 2019)
Unfortunately, after five years we have to announce the end of the HDEV experiment. Originally it should already be over in 2016 and we are pleased that we could inspire you far beyond with the live videos from the ISS. Of course, we will stay with you and continue to bring Earth observation with other great sensors from the ISS into your classroom.
Edit: The information I quoted has now been removed
I just received the notice in the ISS mobile app "We regret to inform you the ISS HDEV has reached End of Life." It was a spectacular gift to have had it this long. My favorite way to pass the time was to watch the world go by, literally. Lol (Edit @bitchaser has the exact wording up above -ty for sharing!)