at the time about 15h daily (now send mail high score), commercial mail system to stop functioning.to send mail I have to restart Zimbra
accessing webmail test receive the following:

"Internal Server Error


The server has encountered an internal error.

Please try again later.

« Go back

ERROR: 500"



Code:
zimbra@server1:~$ zmcontrol -v
Release 6.0.0_GA_1805.UBUNTU9 UBUNTU9 FOSS edition.

Code:
ct 28 15:08:09 server1 postfix/smtpd[6096]: connect from unknown[192.168.2.52]
Oct 28 15:08:09 server1 saslauthd[2584]: zmauth: authenticating against elected url 'https://mydomain.com.vn:7071/service/admin/soap/' ...
Oct 28 15:08:09 server1 saslauthd[2584]: zmpost: url='https://mydomain.com.vn:7071/service/admin/soap/' returned buffer->data='<soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope"><soap:Header><context xmlns="urn:zimbra"/></soap:Header><soap:Body><soap:Fault><soap:Code><soap:Value>soap:Sender</soap:Value></soap:Code><soap:Reason><soap:Text>authentication failed for tranmyhuong@mydomain.com.vn</soap:Text></soap:Reason><soap:Detail><Error xmlns="urn:zimbra"><Code>account.AUTH_FAILED</Code><Trace>btpool0-26:1256717289426:7c9b6cb57d6eec92</Trace></Error></soap:Detail></soap:Fault></soap:Body></soap:Envelope>', hti->error=''
Oct 28 15:08:09 server1 saslauthd[2584]: auth_zimbra: tranmyhuong@mydomain.com.vn auth failed: authentication failed for tranmyhuong@mydomain.com.vn
Oct 28 15:08:09 server1 saslauthd[2584]: do_auth         : auth failure: [user=tranmyhuong@mydomain.com.vn] [service=smtp] [realm=mydomain.com.vn] [mech=zimbra] [reason=Unknown]
Oct 28 15:08:09 server1 postfix/smtpd[6096]: warning: unknown[192.168.2.52]: SASL LOGIN authentication failed: authentication failure
Oct 28 15:08:09 server1 postfix/smtpd[6096]: disconnect from unknown[192.168.2.52]
Oct 28 15:08:34 server1 zmmailboxdmgr[4166]: status requested
Oct 28 15:08:34 server1 zmmailboxdmgr[4166]: status OK
Oct 28 15:08:35 server1 zmmailboxdmgr[4231]: status requested
Oct 28 15:08:35 server1 zmmailboxdmgr[4231]: status OK
Oct 28 15:09:17 server1 postfix/anvil[3357]: statistics: max connection rate 2/60s for (smtp:203.210.204.228) at Oct 28 15:04:11
Oct 28 15:09:17 server1 postfix/anvil[3357]: statistics: max connection count 1 for (smtp:192.168.2.41) at Oct 28 14:59:17
Oct 28 15:09:17 server1 postfix/anvil[3357]: statistics: max cache size 4 at Oct 28 14:59:17
Oct 28 15:09:53 server1 zmmailboxdmgr[5423]: status requested
Oct 28 15:09:53 server1 zmmailboxdmgr[5423]: status OK
Oct 28 15:09:53 server1 zmmailboxdmgr[5488]: status requested
Oct 28 15:09:53 server1 zmmailboxdmgr[5488]: status OK
Oct 28 15:10:01 server1 zimbramon[5562]: 5562:info: 2009-