Hi Hirakjyoti Sarma, Could you identify the MPICH version? -- Hui Zhou From: Hirakjyoti Sarma via discuss <[email protected]> Date: Monday, January 4, 2021 at 10:59 AM To: [email protected] <[email protected]> Cc: Hirakjyoti Sarma <[email protected]> Subject: [mpich-discuss] [discuss-mpich]Error while using mpirun Dear all, I get the following error while running LAMMPS on ubuntu without an internet connection. Invalid error code (-2) (error ring index 127 invalid) Invalid error code (-2) (error ring index 127 invalid) INTERNAL ERROR: invalid error code fffffffe (Ring Index out of range) in MPID_nem_tcp_init:373 Fatal error in PMPI_Init: Other MPI error, error stack: MPIR_Init_thread(586)..............: MPID_Init(224).....................: channel initialization failed MPIDI_CH3_Init(105)................: MPID_nem_init(324).................: MPID_nem_tcp_init(175).............: MPID_nem_tcp_get_business_card(401): MPID_nem_tcp_init(373).............: gethostbyname failed, hirakjyoti-HP-dx2480-MT-KL969AV (errno 0) But if the PC is connected to internet LAMMPS successfully run. How can i solve the problem? Regards, Hirak