I have a Late 2012 Mac Mini running iOS 10.10.5. On the Mail application, I have 2 Yahoo accounts, 4 Gmail, and one iCloud. For some reason, in the past few weeks, one of the Yahoo accounts won't update the email that has been read on my iPhone or Macbook. So, I have to go through all the emails to mark them as read on my Mac Mini. Again, it's only happening to one of the Yahoo accounts, but I can't figure out a solution. Any thoughts?