android - ParseException: Invalid session token error -

i did simple sign user interface check parse reason every time try register user gives me error

this code:

final progressdialog dlg = new progressdialog(this);     dlg.settitle("please wait.");     dlg.setmessage("signing up.  please wait.");     dlg.show();      string username_str = username.gettext().tostring();     string password_str = password.gettext().tostring();     string re_password_str = re_password.gettext().tostring();     string email_str = email.gettext().tostring();     string phone_str = phone.gettext().tostring();      if(!re_password_str.equals(password_str)){         dlg.dismiss();         toast.maketext(this,"passwords not match!!",toast.length_short).show();         password.settext("");         re_password.settext("");     }else if(email_str.isempty()|| phone_str.isempty()){         dlg.dismiss();         toast.maketext(this,"email or phone cannot empty!!",toast.length_short).show();      }else {         parseuser new_user = new parseuser();         new_user.setusername(username_str);         new_user.setpassword(password_str);         new_user.setemail(email_str);         new_user.put("phone", phone_str);         new_user.signupinbackground(new signupcallback() {             @override             public void done(parseexception e) {                 dlg.dismiss();                 if(e == null){                     intent = new intent(signupactivity.this,mainactivity.class);                     startactivity(i);                 }else{                     log.d("signup error", e.tostring());                     toast.maketext(signupactivity.this,e.tostring(),toast.length_short).show();                 }             }         }); 

i've spent 2 days in finding problem without success....

i have deleted manually data parse database. after having error when trying save new user in background:

com.parse.parserequest$parserequestexception: invalid session token

my solution uninstall apk , install again. solved session problem me.