My Fire TV Stick NBC-Universal apps stopped working, apparently due to failed Cox log ins. This includes Paramount and USA network apps. All other networks are fine.

My Fire TV Stick NBC-Universal apps stopped working, apparently due to failed Cox log ins. This includes Paramount and USA network apps. All other networks are fine. This is because it redirects you to the Cox website to log in.
I am entering my correct username and PW, but it only attempts to connect, then backs out to the menu to select provider.
These NBC-Universal apps work fine on my iPhone because they do not direct you to the Cox website.
I have followed all of the possible Fire Stick procedures: rebooted & reset the stick, force-stopped the app, cleared cache, etc. to no avail.
I contacted NBC and was emailed back the following response:

Hi - Thanks for reaching out; we're sorry for the inconvenience.

Our apps get confused when you're signed in on a device but your provider needs you to sign in again to our apps, or if you're signed in to an old provider on the device and trying to switch in our apps. Signing out fully on the Fire device (not just within our app) solves this problem for almost everyone.

Below is a screenshot of my television showing the info of my app's help menu.

Please help. Thanks.