Only halt of jobs are success with remote execution

Hello,
I’m facing strange behaviour.
When i launch a ssh remote execution job for 20 servers for exemple, only 10 are success,
i make a rerun on failed, only 5 are success.
rerun on 5, 3 are ok, etc until all are ok

the message is
1:Error initializing command: RuntimeError - Unable to create directory on remote system /var/tmp/foreman-ssh-cmd-4154505a-861d-47df-bfb4-b7900763b265: exit code: 255
2:ssh: connect to host 172.31.1.78 port 22: Connection timed out
3:Exit status: EXCEPTION

but no connexion pbm for theses server when i launch a job one by one

What could cause this ?

My first bet would be on you having multiple proxies so the job gets load balanced across them and quite possibly not all hosts are reachable from all proxies. How does that sound?

hello, thanks for your answer.
no they use all the same proxy