can receive but can't send these days

[joeyjy]

My gosh! I found my roundcube only can receive mail but failed to send...
roundcube tells me the email is successfully sent but I have tried my gmail, yahoo, hotmail...nothing was received !!
How can I fix it or troubleshot?

[SKaero]

Any error messages?

[joeyjy]

Any error messages?

today's two kinds of error found in the "error" file:
[25-Oct-2012 10:53:58 +0800]: PHP Error: Invalid compose ID in /var/www/html/roundcubemail-0.5.1/program/steps/mail/sendmail.inc on line 33 (POST /roundcube/?_unlock=loading1351133464772?_task=mail&_action=send)
[25-Oct-2012 10:58:42 +0800]: PHP Error: Could not convert string from GBK to UTF-8. Make sure iconv/mbstring is installed or lib/utf8.class is available. in /var/www/html/roundcubemail-0.5.1/program/include/main.inc on line 309 (GET /roundcube/?_task=mail&_remote=1&_action=list&_mbox=INBOX&_refresh=1&_=1351133750378&_unlock=loading1351133750374)

and in the "sendmail" file I found all the mail is sent successfully:
[25-Oct-2012 10:49:42 +0800]: User [email protected] [74.125.176.28]; Message for [email protected]; 250: OK id=1TRDVt-00043K-Vm
[25-Oct-2012 10:57:36 +0800]: User [email protected] [116.246.41.34]; Message for [email protected]; 250: OK id=1TRDdY-0004dn-Ns
[25-Oct-2012 10:59:56 +0800]: User [email protected] [116.246.41.34]; Message for [email protected]; 250: OK id=1TRDfo-0004ll-LA
[25-Oct-2012 11:01:46 +0800]: User [email protected] [116.246.41.34]; Message for [email protected]; 250: OK id=1TRDha-0004t6-5p
[25-Oct-2012 11:47:37 +0800]: User [email protected] [116.246.41.34]; Message for [email protected]; 250: OK id=1TREPx-00073G-Og
[25-Oct-2012 12:37:39 +0800]: User [email protected] [116.246.41.34]; Message for [email protected]; 250: OK id=1TRFCN-0001AG-JC

[SKaero]

Well a good start would be to upgrade RoundCube to the latest version, but from the logs it looks like it maybe a problem with the mail server not RoundCube.

[joeyjy]

Well a good start would be to upgrade RoundCube to the latest version, but from the logs it looks like it maybe a problem with the mail server not RoundCube.

Yes, it's our server's problem. It's fixed now! Thank you Admin