The license code is only used for the TurboTax desktop CD/Download editions, not the TurboTax online editions.
If you purchased the 2019 TurboTax desktop software you should have installed the software on your personal computer to complete the 2019 tax return, not the online editions.
Download the 2019 tax data file from the online edition and finish the tax return on the computer where the software is installed.
See this TurboTax support FAQ for downloading the tax data file - https://ttlc.intuit.com/community/saving/help/how-do-i-save-my-turbotax-online-return-as-a-tax-data-...
