Gospel of Matthew - Matthew 11:1-15 - "The Homeland Tour"

In John 1:29, John the Baptist declared of Jesus, “Behold, the Lamb of God, who takes away the sin of the world.” John the Baptist also said of Jesus, “The strap of whose sandal I am not worthy to untie” (John 1:27), and, “I need to be baptized by you, and do you come to me?” (Matthew 3:14). It is clear that John the Baptist recognized Jesus to be the Messiah and had faith in Him. However, later, as recorded in Matthew 11:3 and Luke 7:19, John the Baptist is in prison. He sends messengers to Jesus to ask Him, “Are you the one who is to come, or should we expect someone else?” What happened? Why was John the Baptist doubting whether Jesus was the Messiah?