Cannot login to Router since Update (Fritzbox Login seit 7.28)

The fritzbox using a random default user name as login, not admin any more for security purpose.
It's the best if you make a new fritzbox user under system -> Fritz!boxUsers. For example user Nodered and give this user sufficient right and a secure password.
Use this user in the node-red-cintrib-fritzapi config screen and it should work fine.