Error on Aws Ec2

Hello guys, I am trying to release my api created on phoenix framework but I am receiving this message:
I am trying to upload my api to aws ec2

crash_report        #{label=>{proc_lib,crash},report=>[[{initial_call,{rpc,init,['Argument__1']}},{pid,<0.1861.0>},{registered_name,[]},{error_info,{error,undef,[{erlang,nif_error,[undef],[]},{maps,new,0,[{file,"maps.erl"},{line,98}]},{rpc,init,1,[{file,"rpc.erl"},{line,104}]},{gen_server,init_it,2,[{file,"gen_server.erl"},{line,374}]},{gen_server,init_it,6,[{file,"gen_server.erl"},{line,342}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,249}]}]}},{ancestors,[kernel_sup,<0.1854.0>]},{message_queue_len,0},{messages,[]},{links,[<0.1856.0>]},{dictionary,[]},{trap_exit,true},{status,running},{heap_size,610},{stack_size,27},{reductions,241}],[]]}
2020-03-31 19:31:27.768892 supervisor_report   #{label=>{supervisor,start_error},report=>[{supervisor,{local,kernel_sup}},{errorContext,start_error},{reason,{undef,[{erlang,nif_error,[undef],[]},{maps,new,0,[{file,"maps.erl"},{line,98}]},{rpc,init,1,[{file,"rpc.erl"},{line,104}]},{gen_server,init_it,2,[{file,"gen_server.erl"},{line,374}]},{gen_server,init_it,6,[{file,"gen_server.erl"},{line,342}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,249}]}]}},{offender,[{pid,undefined},{id,rex},{mfargs,{rpc,start_link,[]}},{restart_type,permanent},{shutdown,2000},{child_type,worker}]}]}
2020-03-31 19:31:27.780885 crash_report        #{label=>{proc_lib,crash},report=>[[{initial_call,{application_master,init,['Argument__1','Argument__2','Argument__3','Argument__4']}},{pid,<0.1853.0>},{registered_name,[]},{error_info,{exit,{{shutdown,{failed_to_start_child,rex,{undef,[{erlang,nif_error,[undef],[]},{maps,new,0,[{file,"maps.erl"},{line,98}]},{rpc,init,1,[{file,"rpc.erl"},{line,104}]},{gen_server,init_it,2,[{file,"gen_server.erl"},{line,374}]},{gen_server,init_it,6,[{file,"gen_server.erl"},{line,342}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,249}]}]}}},{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,[<0.1852.0>]},{message_queue_len,1},{messages,[{'EXIT',<0.1854.0>,normal}]},{links,[<0.1852.0>,<0.1851.0>]},{dictionary,[]},{trap_exit,true},{status,running},{heap_size,987},{stack_size,27},{reductions,219}],[]]}
2020-03-31 19:31:27.788162 std_info            #{label=>{application_controller,exit},report=>[{application,kernel},{exited,{{shutdown,{failed_to_start_child,rex,{undef,[{erlang,nif_error,[undef],[]},{maps,new,0,[{file,"maps.erl"},{line,98}]},{rpc,init,1,[{file,"rpc.erl"},{line,104}]},{gen_server,init_it,2,[{file,"gen_server.erl"},{line,374}]},{gen_server,init_it,6,[{file,"gen_server.erl"},{line,342}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,249}]}]}}},{kernel,start,[normal,[]]}}},{type,permanent}]}
{"Kernel pid terminated",application_controller,"{application_start_failure,kernel,{{shutdown,{failed_to_start_child,rex,{undef,[{erlang,nif_error,[undef],[]},{maps,new,0,[{file,\"maps.erl\"},{line,98}]},{rpc,init,1,[{file,\"rpc.erl\"},{line,104}]},{gen_server,init_it,2,[{file,\"gen_server.erl\"},{line,374}]},{gen_server,init_it,6,[{file,\"gen_server.erl\"},{line,342}]},{proc_lib,init_p_do_apply,3,[{file,\"proc_lib.erl\"},{line,249}]}]}}},{kernel,start,[normal,[]]}}}"}
Kernel pid terminated (application_controller) ({application_start_failure,kernel,{{shutdown,{failed_to_start_child,rex,{undef,[{erlang,nif_error,[undef],[]},{maps,new,0,[{file,"maps.erl"},{line,98}]}

I already reinstall elixir and erlang.
I am quite newbie on that framework, someone can help me ?

If you built a release then maybe make sure you built it on the same OS that you are trying to run it on. If you didn’t build a release and you are trying to run it on ec2 with mix phx.server or similar then make sure you have the same version of Erlang and Elixir installed on the EC2 instance. You should be able to run elixir -v and erl -v on the EC2 instance to verify.

Exactly how @brucepomeroy said. Maybe you can explain us the steps you’re doing?