title: delete() does not work sometimes
body: <p>I am setting up an account deactivation activity in my app but the <code>user.delete()</code> method does not work sometimes...</p>
  
  <p>The fact that it works sometimes and does not some other time is really confusing... If it's a logic error it should not work all of the time right?</p>
  
  <p>this is the code that I have</p>
  
  <pre><code>deactivateAccount.setOnClickListener(new View.OnClickListener() {
      final FirebaseUser user = mAuth.getCurrentUser();
  
      @Override
      public void onClick(View view) {
          deletePosts();
          deleteComments();
          deleteLikes();
          deleteUser();
          user.delete().addOnCompleteListener(new OnCompleteListener&lt;Void&gt;() {
              @Override
              public void onComplete(@NonNull Task&lt;Void&gt; task) {
  
                  Toast.makeText(DeactivateAccount.this, "You account has been deactivated",Toast.LENGTH_LONG).show();
                  Intent loginIntent = new Intent (DeactivateAccount.this, LoginActivity.class);
                  startActivity(loginIntent);
  
              }
  
          });
  
  
      }
  </code></pre>
  
  <p>There is no error so I don't know how to debug this as well... but the deletePosts(), deleteComments(), deleteLikes(), and deleteUser() methods all work perfectly... but it leaves the user undeleted in the authentication tab... their e-mail is still there.</p>
  
  <p>Many thanks!</p>