The second flaw is that we're not expected to preach God's name.
Acts 20:20-21, the 'go to' verse to prove the door to door work says:
"...while I did not hold back from telling you any of the things that were profitable nor from teaching you publicly and from house to house. But I thoroughly bore witness both to Jews and to Greeks about repentance toward God and faith in our Lord Jesus."
So the message should be "repent and have faith in Jesus", not "God's name is Jehovah".