title: mpiexec - Credentials for user rejected connecting host
body: <p>To do some exercise to be more familiar with MPI, i installed MS-MPI on my windows 10 machine, and then mpi4py (python MPI). I tried a hello_world code:</p>
  
  <pre><code>from mpi4py import MPI
  
  def main ():
      comm = MPI. COMM_WORLD
      rank = comm . Get_rank ()
      size = comm . Get_size ()
      print " hello from " + str( rank ) + " in " + str( size )
  
  
  if __name__ == " __main__ ":
      main ()
  </code></pre>
  
  <p>Then, with a windows command as admin i executed the following command:</p>
  
  <pre><code>mpiexec -n 8 python MPI_Test.py
  </code></pre>
  
  <p>I get: </p>
  
  <blockquote>
    <p>User credentials needed to launch processes: account (domain\user)
    [DESKTOP-3CFSBJ8\Hazem]:</p>
  </blockquote>
  
  <p>I did a registration, as mpiexec - register from username/pwd, then execute again that command, and i get the following error:</p>
  
  <blockquote>
    <p>Credentials for user rejected connecting to host.</p>
  </blockquote>
  
  <p>THE PROBLEM COMES WHEN EXECUTING THE COMMAND mpiexec.</p>