to_datetime method

I tried to run this method and save chenges but got an error " RuntimeError: The string provided for NumPy ISO datetime formatting was too short, with length 11'

the method works fine on it's own

pd.to_datetime(real_estate[:,2] >> works fine

but when I try to assign an object to it , it returns the above error

real_state[:, 2] = pd.to_datetime(real_estate[:,2] >> error

how can I fix this errror