I was getting the same thing. I uninstalled the app, and re-installed from the play store. Looks like they got a new app, and the old app does not work any more. So uninstall old, and install new.
The old one was published under contracted company’s account which is no longer available. To ensure security and continue improvements we developed new app from scratch in-house and de-authorized the old app. We notified customers about the new app earlier in the year, but it looks like emailing missed some of the accounts. From now on the updates will be delivered automatically through this new listing.