Twitter just announced that it will be shutting down the Twitter Dashboard as of February 3, 2017. The Twitter Dashboard included many useful tools for businesses and marketers, such as: tweets tracking tools, post scheduling, tweet monitoring and analytics and more.
Rumor has it that Twitter has have not been happy with the Twitter Dashboard performance and it's potential overlap with other like apps. Twitter is expected to release a newer and better version of Twitter Dashboard in the months to come.