Yes. In HealthCare.gov states, when you first applied for coverage, you had the opportunity to authorize the Marketplace to check online income data about you, including from your tax returns, for another 1 to 5 years. If you did not authorize this (note that most people did give authorization), your financial assistance will NOT be automatically continued for next year. You must re-apply for financial assistance if you want the APTC to continue for another year.
Note that the process for renewing financial assistance may vary in other states. All state Marketplaces will send consumers notices prior to the start of Open Enrollment explaining the process for continuing or re-applying for financial assistance for the coming year.