Return value of solvepnpransac

I have a set of 2D-3D points, but they are not completely corresponding,may be a bit of mismatch. I think that using this set of points as the input of solvepnpransac will select the inner points and perform PNP solution and return one optimal rev and tec,however, the actual return value is very abnormal(tvec:like 10^20 or inf),how is it that?