To configure Two-factor Authentication via SMS, do the following:

1. Open the ‘Services Configuration’ window.

2. Double-click the ‘Two-factor Authentication‘ service. 

3. Click the ‘Edit‘ button. 

4. In the opened window, enter the Mobile number and some text, ad click the ‘Test‘ button to check if the configuration is correct.
Example: 

5. Click the ‘Test‘ button to check the SMTP configuration.

6. Enter the following data for the test – username, email and some OTP code, and click the ‘Test Connection‘ button.
For example: 

In case of a successful connection, a test message is sent to the specified mobile number, and the relevant pop-up message is shown.

7. Click the ‘OK‘ button to save changes.