I’ve had no issues at all. Did you log into the JNUC website first before setting up your login in the app?

Yes. I logged into the website first. 

Maybe delete the app and then redownload it and see if you’re still having issues.

I haven’t had any issues at all. However, my JNUC login is separate from my Jamf Account login. Even though it’s the same email addresses they are separate passwords. 

I was able to reset the password on the website it allowed me in. But it is also separate from my Jamf Account. It is what was used to register for JNUC.