Couple of things: this is your first post, so the phase "your fix" has no meaning, as we have no idea who you're talking to, nor what "fix" that mysterious person suggested.
So, shooting completely in the dark (well, not completely, as the model number and software version you supplied are very helpful): did you reboot the Roku? Did that resolve it?
Did you try to force an update of the Roku? Settings > System > System update
If that didn't work, did you remove the app, then reboot the Roku, then reinstall the app -- all three steps in that order -- and log in again?
If that didn't work, did you remove the app, reboot the Roku, then add the app via https://channelstore.roku.com/ then log in again within the app?
What is your TV provider against which you are authenticating? NBC will only play a few items of content before it requires you to authenticate against a TV (cable, satellite, streaming) content provider.
So, if you can provide some additional informaiton, perhaps we can figure this out and get things working like you're wanting.
Roku Community Streaming Expert
Note: I am not a Roku employee.
If this post solves your problem please help others find this answer and click "Accept as Solution."