[Exim] exim manualroute problem

Hi guys!

Im using exim as manual router to filter emails for viruses, spam and
blacklists.
If all's fine exim will forward the mail to the master mailserver.

My manualroute rule is:

smart_route:
    driver = manualroute
    domains = +relay_to_domains
    transport = remote_smtp
    route_list = domain1.at smtp.mailserver2.at; \
                 domain2.at smtp.mailserver2.at;

that works fine, but if i enable callout checking with

  accept  domains       = +relay_to_domains
          endpass
          verify        = recipient/callout=10s,defer_ok

the callout fails after some time for the whole domain1.at with the error:

2004-04-20 11:24:36 H=mail1.dexia-bil.lu (smtpplm1.dexia-bil.com)
[156.133.50.70] F=<dexiamail@???> rejected RCPT <user@???>:
(result of an earlier callout reused).

But the rcpt user exists on the destination system.

what could be the reason for this error?

greetings,

Florian Schicker
Nessus.at Internet Services
A-1050 Wien. Nikolsdorfergasse 42/17
fon 0810.900.686 (Ortstarif nur aus Österreich)
fon +43.676.3388033
fax +43.1.9208839

fs@???
www.nessus.at