xfinity app gateway offline still have internet

Recently upgraded to a new Xfinity Gateway modem.  Now the app shows that the Gateway is offline even though I have internet service.  I am unable to change / monitor any users on the app.  I cannot modify down time or parental controls or any user profiles since the app thinks the Gateway if offline.  Please advise.  The app is completely useless when it thinks the Gateway is offline.  I went into an Xfinity store and inquired about this issue and they just said to wait a few days.  It has been almost a week and still no change.  I have deleted the app and re-downloaded it, and signed in again.  No change.  Please, please advise on how to fix this issue. I need to be able to manage my children's internet access and use.