Question about Laminar flow over flat plate in FLUENT
 

I`m running a classical case: laminar flow(air) over flat plate. However, when I compare my u/Uinf to Blasius solution, it`s always overshoot 1 and does not match with the Blasius solution very well. (as in the picture)
I don`t know why. Can anyone give me some help there? I will be really appreciate.

I`m giving the Boundary conditions:
Left:velocity inlet: x=1, y=0. T=300K
Right: pressure outlet, leave the default pressure as in 0.
Top: Velocity inlet: x=1, y=0 T=300K (I tried the Cornell University`s tutorial set it as symmetry, it still overshoot 1)
Bottom: Isothermal wall. T=400K