Yes. I had to perform a factory reset, because I think I've tried everything. Changed the password on android device manager and blocked again. It appeared the new password, I have deblocked again, went to Settings -> Security -> Screen lock entered the new password and I choose None. I restarted the phone but it keept appearing me the text "locked by android device manager". After the phone ringed on phone that I set on androide device manager I could enter the phone without entering the pasword.
So I performed a factory reset and erased everything from the phone and got rid of all the problems.
I use an zte blade q maxi phone.