[exim] Refused: too many connections from that IP address

Hi, list!

Today I notice that my Exim refused many connection from my PC
(AUTHENTICATED!) with the error:

Connection from [X.Y.Z.K] refused: too many connections from that IP
address

Normally I would say, it is normal to refuse the connection coming from the
same IP that sends too many E-Mails, but it was Nagios to send these E-Mails,
and I need to have these E-Mails delivered...

I couldn't find any restriction for the authenticated users. I just have this
rule in acl_check_helo:

  defer   message         = Sender rate exceeds $sender_rate_limit messages
  per $sender_rate_period
          ratelimit       = 1000 / 1h / per_conn / leaky / $sender_host_address

So, how can I have a rate limit for NON authenticated E-Mails, but no
restriction for the authenticated ones?

Thanks a lot!
Luca Bertoncello
(lucabert@???)