How to solve the problem with Russian encoding when writing text in richTextBox?

Question

C++ / C#

There was a problem when displaying the Russian language from the log in richTextBox1.Text Krakozyabry
appears instead of normal text, how to solve it?

else if (richTextBox1.InvokeRequired)
      {
        richTextBox1.Invoke(new MethodInvoker(() =>
        {
          if (richTextBox1.Text.Length > 3000)
          {
            richTextBox1.Text = richTextBox1.Text.Remove(0, messages.Length);
          }
          byte[] msg = Encoding.Default.GetBytes(messages);
          richTextBox1.Text = string.Concat(richTextBox1.Text, "\r\n", Encoding.Default.GetString(msg));
          richTextBox1.SelectionStart = richTextBox1.Text.Length;
          richTextBox1.ScrollToCaret();
        }));
      }