Failed delivery on send

[nfranke]

When I send email to some accounts from RC, it sometimes (depending 
on who I'm sending to) never makes it, and sometimes I get an error:

    xxx.biz[xx.xx.xx.xx] said: 550 Requested action not taken:
    Nonstandard SMTP line terminator. (in reply to end of DATA command)

I suspect the ones who never get it aren't because of this error, their 
mailers just never send something back.

I've tried sending to the same person from other web mail clients, and 
they work correctly all the time to all accounts.

So, is RC not using CR LF for termination?

[nfranke]

Logged In: YES 
user_id=1212546

I decided to do a tcpdump of mail from RC and mail from another webmai client. 
After removing the the non-text parts, they are clearly different. RC is adding 
additional ^M characters after each line in the header and body. I think this is 
the cause of the problem. Lines must be terminated with CR LF, but we are 
getting CR CR LF, as a hex dump "0d 0d 0a"

[roundcube]

Logged In: YES 
user_id=1262041

The header delimiter can be configured:
$rcmail_config['mail_header_delimiter']

Only use \n on unix systems if no SMTP server is configured.