Hi. I’m learning OTP and elixir by reading the book The Little Elixir and OPT GuideBook. I’m on chapter 8 and while trying to run this application call Blitzy that of spawns some workers to hit a DNS address using HTTP requests, I got this error:

2019-09-23 22:05:02.871212
    args: []
    format: "Can't set short node name!\nPlease check your configuration\n"
    label: {error_logger,info_msg}
2019-09-23 22:05:02.871941 crash_report        #{label=>{proc_lib,crash},report=>[[{initial_call,{net_kernel,init,['Argument__1']}},{pid,<0.59.0>},{registered_name,[]},{error_info,{exit,{error,badarg},[{gen_server,init_it,6,[{file,"gen_server.erl"},{line,358}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,249}]}]}},{ancestors,[net_sup,kernel_sup,<0.46.0>]},{message_queue_len,0},{messages,[]},{links,[<0.56.0>]},{dictionary,[{longnames,false}]},{trap_exit,true},{status,running},{heap_size,610},{stack_size,27},{reductions,411}],[]]}
2019-09-23 22:05:02.875989 supervisor_report   #{label=>{supervisor,start_error},report=>[{supervisor,{local,net_sup}},{errorContext,start_error},{reason,{'EXIT',nodistribution}},{offender,[{pid,undefined},{id,net_kernel},{mfargs,{net_kernel,start_link,[['d@127.0.0.1',shortnames],true]}},{restart_type,permanent},{shutdown,2000},{child_type,worker}]}]}
2019-09-23 22:05:02.895237 supervisor_report   #{label=>{supervisor,start_error},report=>[{supervisor,{local,kernel_sup}},{errorContext,start_error},{reason,{shutdown,{failed_to_start_child,net_kernel,{'EXIT',nodistribution}}}},{offender,[{pid,undefined},{id,net_sup},{mfargs,{erl_distribution,start_link,[]}},{restart_type,permanent},{shutdown,infinity},{child_type,supervisor}]}]}
2019-09-23 22:05:02.904502 crash_report        #{label=>{proc_lib,crash},report=>[[{initial_call,{application_master,init,['Argument__1','Argument__2','Argument__3','Argument__4']}},{pid,<0.45.0>},{registered_name,[]},{error_info,{exit,{{shutdown,{failed_to_start_child,net_sup,{shutdown,{failed_to_start_child,net_kernel,{'EXIT',nodistribution}}}}},{kernel,start,[normal,[]]}},[{application_master,init,4,[{file,"application_master.erl"},{line,138}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,249}]}]}},{ancestors,[<0.44.0>]},{message_queue_len,1},{messages,[{'EXIT',<0.46.0>,normal}]},{links,[<0.44.0>,<0.43.0>]},{dictionary,[]},{trap_exit,true},{status,running},{heap_size,610},{stack_size,27},{reductions,194}],[]]}
2019-09-23 22:05:02.924339 std_info            #{label=>{application_controller,exit},report=>[{application,kernel},{exited,{{shutdown,{failed_to_start_child,net_sup,{shutdown,{failed_to_start_child,net_kernel,{'EXIT',nodistribution}}}}},{kernel,start,[normal,[]]}}},{type,permanent}]}
{"Kernel pid terminated",application_controller,"{application_start_failure,kernel,{{shutdown,{failed_to_start_child,net_sup,{shutdown,{failed_to_start_child,net_kernel,{'EXIT',nodistribution}}}}},{kernel,start,[normal,[]]}}}"}
Kernel pid terminated (application_controller) ({application_start_failure,kernel,{{shutdown,{failed_to_start_child,net_sup,{shutdown,{failed_to_start_child,net_kernel,{'EXIT',nodistribution}}}}},{ker

Crash dump is being written to: erl_crash.dump...done

This happens when after initializing 3 instances of my Ubuntu terminal I start up new nodes on each by running the command:

iex --sname d@127.0.0.1 -S mix