Contradiction with Mark 16:11
This verse contradicts John 20:18 as it states that when Mary told the disciples that Jesus was alive, they did not believe her.
Mark 16:11: And they, when they had heard that he was alive, and had been seen of her, believed not.
Contradiction with Luke 24:11
This verse contradicts John 20:18 by indicating that the apostles considered Mary Magdalene's report of the resurrection as idle talk and did not believe her.
Luke 24:11: And their words seemed to them as idle tales, and they believed them not.