Error "Data Extract Required" Saving Workbook to Tableau Public

Issue

When saving a workbook to Tableau Public, the following message occurs:

Data Extract Required

The Tableau server you are publishing to does not permit external database connections. Use the Data menu to create an extract for the following data source:
<data-source-name>

User-added image

Environment

Tableau Public
Tableau Desktop Public
Live data connection

Resolution

For a workbook that uses a live connection to a supported data source, you must create an extract in Tableau Desktop Public before you can publish the workbook to Tableau Public (web).

Follow these steps:

Create an extract of the data source by clicking on 'Activate Data Extract' in the message displayed.

Save the workbook to Tableau Public.

Here are some additional troubleshooting steps:

Go to the bottom of the visualization and find your name toward the right. Click on the little downward triangle and choose Sign Out. Then, go to File and try Save to Tableau Public again. You might have to try this a few times, because this issue can happen intermittently.
Go to the top menu and select Help > Settings & Performance > and select Clear Saved Server Sign-ins.
Use Save to Tableau Public As and choose a different file name.
Copy the workbook sheets to a new workbook and try saving that one.

Cause

Tableau Desktop Public Edition and Tableau Public (web) work with data from Microsoft Excel, Microsoft Access, multiple text file formats, statistical files, and web data connectors.

Additional Information

The Tableau Desktop Public Edition does not usually display this error message; but, there might be a somewhat different error. This is because Tableau Desktop Public automatically saves an extract (.tde) of the data source as a temporary file when publishing the workbook to Tableau Public on the web (as a .twbx).