android - How to make sign out from firebase -

this code using firebase sign in. after completing verification signing out. when try sign in again same number doesn't send me otp.

help me signout it. in advance. code:

 @override public void onverificationcompleted(phoneauthcredential credential) {  // callback invoked in 2 situations:  // 1 - instant verification. in cases phone number can instantly  //     verified without needing send or enter verification code.       // 2 - auto-retrieval. on devices google play services can automatically  //     detect incoming verification sms , perform verificaiton without  //     user action. // log.d(tag, "onverificationcompleted:" + credential);     //mauth.signout();      mauth= firebaseauth.getinstance();      if(mauth!=null)          mauth.signout();      toast.maketext(mainactivity.this,"verification complete",toast.length_short).show(); 

}

 @override  public void oncodesent(string verificationid,     phoneauthprovider.forceresendingtoken token) {  // sms verification code has been sent provided phone number,  // need ask user enter code , construct credential  // combining code verification id. //   log.d(tag, "oncodesent:" + verificationid);      toast.maketext(mainactivity.this,"code sent",toast.length_short).show();  // save verification id , resending token can use them later  mverificationid = verificationid;  mresendtoken = token; mobilenumber.setvisibility(view.gone);      submit.setvisibility(view.gone);     otpbutton.setvisibility(view.visible);      otptext.setvisibility(view.visible);      t1.setvisibility(view.gone);      t2.setvisibility(view.visible);      mauth= firebaseauth.getinstance();  }   otpbutton.setonclicklistener(new view.onclicklistener() {         @override         public void onclick(view v) {             phoneauthcredential credential = phoneauthprovider.getcredential(mverificationid,otptext.gettext().tostring());             signinwithphoneauthcredential(credential);         }     });      submit.setonclicklistener(new view.onclicklistener() {         @override         public void onclick(view v) {             phoneauthprovider.getinstance().verifyphonenumber(                     "+91"+mobilenumber.gettext().tostring(),// phone number verify                     60,// timeout duration                     timeunit.seconds,// unit of timeout                     mainactivity.this,// activity (for callback binding)             mcallbacks);         }     }); }  private void signinwithphoneauthcredential(phoneauthcredential credential) {  mauth.signinwithcredential(credential) .addoncompletelistener(this, new oncompletelistener<authresult>() {      @override      public void oncomplete(@nonnull task<authresult> task) {          if (task.issuccessful()) {              toast.maketext(mainactivity.this,"verification                   done",toast.length_short).show();             firebaseuser user = task.getresult().getuser();         } else {         if (task.getexception() instanceof              firebaseauthinvalidcredentialsexception) {                toast.maketext(mainactivity.this,"verification failed code                  invalid",toast.length_short).show();          }         }      }  }); }