Contradiction with James 4:2
James 4:2 suggests that people do not have because they do not ask, while in Mark 10:51, the blind man asks Jesus directly for what he desires.
James 4:2: Ye lust, and have not: ye kill, and desire to have, and cannot obtain: ye fight and war, yet ye have not, because ye ask not.
Contradiction with Matthew 6:8
This verse states that God knows what you need before you ask, in contrast to Mark 10:51, where Jesus asks the blind man what he wants.
Matthew 6:8: Be not ye therefore like unto them: for your Father knoweth what things ye have need of, before ye ask him.
Contradiction with John 14:13
John 14:13 implies that whatever is asked in Jesus' name will be granted, while Mark 10:51 shows an example of someone asking directly yet with a specific interaction needed.
John 14:13: And whatsoever ye shall ask in my name, that will I do, that the Father may be glorified in the Son.
Contradiction with Isaiah 65:24
Implies that God will answer before they call, which contrasts with Mark 10:51 where a specific request is made by the individual.
Isaiah 65:24: And it shall come to pass, that before they call, I will answer; and while they are yet speaking, I will hear.