Inspired from the running discussion about sending invites I tried to get this run via an external mail server. But I failed because my server announces auth via "cram-md5" but can't handle it. Now I tried to get my server to not propagating this auth-method, but without success. So I tried to get Darwin Calendar Server to use "plain auth", but I failed too. I would be happy if anyone can give me a clue. My system: DCS on Leopard 10.5 (same on the test system with 10.6.7) failure: 2011-04-04 23:51:35+0200 [-] [mailgateway] 2011-04-04 23:51:35+0200 [ESMTPSender,client] [twistedcaldav.mail.MailHandler#error] Mail gateway failed to send message <20110404215130.38446.1328247023.0@server.local> from xxx@xxx.com to mailto:yyy@yyy.com (Reason: 535 authorization failed (#5.7.0) 2011-04-04 23:51:35+0200 [-] [mailgateway] >>> AUTH CRAM-MD5 2011-04-04 23:51:35+0200 [-] [mailgateway] <<< 334 PDEzNjE1LjEzMDE5NTQzNjRAaDQ5NjYxPg== 2011-04-04 23:51:35+0200 [-] [mailgateway] >>> ZGNzQHJhZGlvZnV6emllLmNvbSA2MTU4OTc5OWE3OThjNzdmOGQzZjc0MGZkMGMyNzNkYQ== 2011-04-04 23:51:35+0200 [-] [mailgateway] <<< 535 authorization failed (#5.7.0) 2011-04-04 23:51:35+0200 [-] [mailgateway] ) 2011-04-04 23:51:35+0200 [-] [caldav-0] [AuthorizedHTTPGetter,client] [twistedcaldav.scheduling.imip#error] Could not do server-to-imip request : <twistedcaldav.scheduling.imip.ScheduleViaIMip object at 0x205a410> 400 Bad Request 2011-04-04 23:51:35+0200 [-] [caldav-0] [AuthorizedHTTPGetter,client] [twistedcaldav.scheduling.scheduler.ScheduleResponseQueue#error] Error during PUT for mailto:j.raehm@gmail.com: None 2011-04-04 23:51:36+0200 [-] [caldav-0] [HTTPChannel,4,xxx.xxx.xxx.xxx] [twext.web2.server#info] GET /calendars/__uids__/xxx/83X8A9X9-ECBC-4X98-9X59-49C0AS832B0E/1C0821DC-645D-4FBE-8A86-C0C76BAE52DE.ics HTTP/1.1 2011-04-05 00:01:00+0200 [-] [caldav-0] [HTTPChannel,5,xxx.xxx.xxx.xxx] [twext.web2.server#info] PROPFIND /calendars/__uids__/xxx/ HTTP/1.1 Thanks a lot & Regards Jan