Hello All: We recently migrated our working Horde IMP installation to a VM. The migrated Horde IMP is working with the exception of sending a message that contains an attachment of any size. Our mail server and our Horde VM are de-coupled. I can verify that when an attachment is added in the compose screen, it is in fact uploaded to the /tmp directory on the server. IMP will send a message without problem when there is NOT an attachment. When the 'Send Message' button is clicked in a message that contains the attachment, the compose screen just sits there and finally I get the following message: "There was an error sending your message: Failed to send data [SMTP: Invalid response code received from server (code: -1, response: )]" I've enabled debugging in the Apache logs and nothing is giving me a clue as to the problem. This is a CentOS 5.5 install with Apache 2.2.3 and PHP v5.2.5. Here's output of the Horde test.php: Horde Version •Horde: 3.2-RC3 Horde Applications •Forwards: H3 (3.0.1) •Horde: 3.2-RC3 •Imp: H3 (4.2-RC3) (run Imp tests) •Ingo: H3 (1.2-RC2) (run Ingo tests) •Mimp: H3 (1.1.1) •Passwd: H3 (3.0.1) (run Passwd tests) •Turba: H3 (2.1.5) (run Turba tests) PHP Version •View phpinfo() screen •View loaded extensions •PHP Version: 5.2.5 •PHP Major Version: 5.2 •PHP Minor Version: 5 •PHP Version Classification: release •You are running a supported version of PHP. PHP Module Capabilities •Ctype Support: Yes •DOM XML Support: Yes •FTP Support: Yes •GD Support: Yes •Gettext Support: Yes •GeoIP Support (via PECL extension): No Horde can optionally use the GeoIP extension to provide faster country name lookups. •Iconv Support: Yes •GNU Iconv Support: Yes •IMAP Support: Yes •JSON Support: Yes •LDAP Support: No LDAP support is only required if you want to use an LDAP server for anything like authentication, address books, or preference storage. •LZF Compression Support: Yes •Mbstring Support: Yes •PCRE Support: Yes •PCRE UTF-8 Support: Yes •Mcrypt Support: Yes •memcached Support (memcache): Yes •MIME Magic Support (fileinfo): Yes •MIME Magic Support (mime_magic): Yes •MySQL Support: Yes •OpenSSL Support: Yes •PostgreSQL Support: No The PostgreSQL extension is only required if you want to use a PostgreSQL database server for data storage. •Session Support: Yes •XML Support: Yes •Zlib Support: Yes Miscellaneous PHP Settings •magic_quotes_runtime disabled: Yes •memory_limit value: 512M If PHP's internal memory limit is not set high enough Horde will not be able to handle large data items (e.g. large mail attachments in IMP). You should set the value of memory_limit in php.ini to a sufficiently high value - at least 64M is recommended. •safe_mode disabled: Yes •session.use_trans_sid disabled: Yes •session.auto_start disabled: Yes •zlib.output_compression disabled: Yes •zend_accelerator.compress_all disabled: Yes File Uploads •file_uploads enabled: Yes •upload_max_filesize: 26214400 •post_max_size: 20971520 Required Horde Configuration Files •config/conf.php: Yes •config/mime_drivers.php: Yes •config/nls.php: Yes •config/prefs.php: Yes •config/registry.php: Yes PHP Sessions •Session counter: 1 •To unregister the session: click here PEAR •PEAR Search Path (PHP's include_path): /var/www/html/horde/lib:.:/usr/local/lib/php •PEAR: Yes •Recent PEAR: Yes •Mail: Yes •Mail_Mime: Yes •Mail_mimeDecode: Yes •Log: Yes •DB: Yes •Net_Socket: Yes •Date: Yes •Auth_SASL: Yes •HTTP_Request: Yes •HTTP_WebDAV_Server: No The HTTP_WebDAV_Server is required, if you want to use the WebDAV interface of Horde, e.g. to access calendars or tasklists with external clients. •Net_SMTP: Yes •Services_Weather: No Services_Weather is used by the weather applet/block on the portal page. •Cache: No Cache is used by the Services_Weather module on the weather applet/block on the portal page. •XML_Serializer: No XML_Serializer is used by the Services_Weather module on the weather applet/block on the portal page. I should note that all settings including php.ini were migrated from a standalone box in which all was working fine. Any takers?? Thanks!!!