Using Exchange Server 2000 I see these 2 errors regularly when sending mail to 2 domains There was a SMTP communication problem with the recipient's email server. Please contact your system administrator. <my.mail.server #5.5.0 smtp;554 Transaction Failed"." on a line by itself> This one almost everytime we send a message to @yahoo.com There was a SMTP communication problem with the recipient's email server. Please contact your system administrator. <my.mail.server #5.5.0 smtp;552 Put ,E=\r\n at the end of Mether, Mtcp, or Msmtp in sendmail.cf if you are using Solaris 2.5 (fixed in 2.5.1). I cannot accept messages with stray newlines. Many SMTP servers will time out waiting for \r\n.\r\n.> Is there anything I can do from my end to resolve these?