Maybe because his regex only match one time, if more than one email is present in a line, it won't catch it, try :

Code:
on *:SOCKREAD:mysock: {
  var %line,%a 
  sockread %line
  if ($regex(%line, /<passportName>(.+?)<\/passportName>/g)) {
  %a = $regml(0)
  while (%a) { echo -a contact: $regml(%a) | dec %a }
 } 
}

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