I'm having some problems with courier rejecting mails with the following error:

450 Service temporarily unavailable. ttes...@example.net: invalid address.

This error showed up immediately after the server accepted an identical message for this user. I'm running the test using this command from the server:

$ sendmail -f bow...@example.com ttes...@example.net

One attempt went through, the next attempt failed with the error shown above. Here are a couple of excepts from the maillog. Why did authdaemond not bind to the LDAP the second time? Is that part of the problem, or is it normal?

This connection worked: authdaemond: received userid lookup request: ttes...@example.net authdaemond: authldap: trying this module authdaemond: selected ldap protocol version 3 authdaemond: binding to LDAP server as #REMOVED# authdaemond: using search filter: (&(objectClass=CourierMailAccount)(mail=ttes...@example.net)) authdaemond: one entry returned, DN: mail=ttes...@example.net,cn=Users,dc=example,dc=net

This connection (5 seconds later) did not: authdaemond: received userid lookup request: ttes...@example.net authdaemond: authldap: trying this module authdaemond: using search filter: (&(objectClass=CourierMailAccount)(mail=ttes...@example.net)) authdaemond: ldap_search_st() failed authdaemond: authldap: TEMPFAIL - no more modules will be tried

Any ideas?

If it makes any difference, the backend is the Fedora Directory Server (v7.1, not the open source version).