First you have to make sure you current Leawo Free Video Converter is the latest one, if not, upgrade it to the newest version. Then there are two cases:
1. With account 2-step verification turned off
You are to normally login in your account and then upload video to YouTube smoothly.
2. With account 2-step verification turned on
Under this circumstance, you are unable to get approach to your account in order to upload video to YouTube. There are two solutions for you:
Solution a. Turn off 2-step verification
Login in your Account via website, choose "Security" as showed below.
Then in the existing interface, select "Edit" to adjust 2-step verification status.
Click on "Turn off 2-step verification" in this interface.
Confirm "OK" to turn off 2-step verification.
Solution b. Get application-specific passwords
Go to Google Account Sign in page, and choose "Can't access your account?".
Then pick up the third option "I'm having other problems signing in" and enter your Email address, then click on "Continue".
Type the characters you see in the picture and click on "Continue".
Choose the second option "I can sign-in from a web browser, but not from my mobile device or applications", click on the hyperlinked text "application-specific passwords", and then click on "Continue".
Within the existing page, click on the hyperlinked text "Authorizing applications & sites page".
It will lead you to the Google Account sign in page again, and then sign in with your Email and Password.
Enter a name in the Name box and click on "Generate password".
You will get application-specific passwords as below.
You can now enter your new application-specific password into the software and click on "Verify".