Why fabric "The Fabric iOS and Android mobile apps will be sunset on November 30, 2018. After this date, you will not be able to log into the apps" is it closing?
Just check this official post. https://get.fabric.io/roadmap
Fabric Beta will be moved into Firebase on Early 2019.
Start using the next generation of Crashlytics Beta Get valuable feedback on pre-release iOS and Android apps by using Firebase App Distribution, the new version of Crashlytics Beta, to distribute beta builds to your team.