Mail connector say some problems

hi ,
i have 2 external mail server. i connect and get the mails. one server work perfekt. but other one say error with no log. it works but it gets no all mails. it lost 10% mails. how can debug it ?
the webserver gui say

1. B {problem: null, exit_status: 1, exit_signal: null, message: "/usr/bin/sudo exited with code 1", toString: ƒ}

  1. problem: null
  2. exit_status: 1
  3. exit_signal: null
  4. message: "/usr/bin/sudo exited with code 1"
  5. toString: ƒ ()
  6. __proto__: Object

any idea ?

Check /var/log/messages and /var/log/maillog