After upgrading from plesk 11 to plesk 11.5 (centos5 64-bits) the horde webmail application is unable to sent e-mail. When sending the message a red dialogue box appears with the message "sendmail internal software error 70". This customer is using postfix in combination with spamassassin. The only way for me to fix this was switching from postfix to qmail. After that the error was gone. Anyone else experienced this?