Hi, take a look at https://www.basvanbeek.nl/linux/prevent ... p-headers/ and viewtopic.php?t=30938

Hi, I think you can achieve this using Policyd integrated in Zimbra. Take a look at https://blog.zimbra.com/2020/03/2-3-zim ... h-policyd/ and https://wiki.zimbra.com/wiki/How-to_for_cbpolicyd .

These "Undelivered mail returned to sender" messages are a symptom of wrong email transit from your mail server. Open one of these emails and look at the error message that they contain.

Hi, take a look at the mail filters on that user mailbox: connect to his webmail -> Preferences -> Filters.

Hi, did you buy a Zimbra Network license or install the 30-days trial license? ZCO works only with Zimbra Network Edition and a valid license, it does not work with Zimbra open source edition. Take a look here: https://zimbra.github.io/installguides/ ... _Activated

Hi, take a look at log files /opt/zimbra/log/mailbox.log and /opt/zimbra/log/zmmailboxd.out to find out what is the reason of mailbox service not starting. Maybe it is a file permission issue, then use this command: https://wiki.zimbra.com/wiki/Fix_the_Zi ... ermissions

Hi, you could try to add Zimbra Global Address List as an address book in Outlook following this guide: https://wiki.zimbra.com/wiki/Configure_ ... in_Outlook

Hi, you could try to use 'mailq' command from zimbra server command line prompt and redirect it to a file. Take a look at https://www.wirehive.com/thoughts/5-top ... ail-queue/

Que yo sepa, la mejor opción es Zextras, es gratis para la migración.

tiene una versión anterior de zimbra, que podría ser vulnerable: http://forums.zimbra.com/viewtopic.php? ... 972f2e4a4c