I am using Zimbra OSS for quite a while, still learning all new things. I do use it regularly as web client. But recently I got new accounts, who would like at least for beginning, to use their regular Outlook and Mac Mail clients, while whole changeover can be implemented.
When configuring IMAP accounts on MS Office Outlook and Mac Mail, as well as IMAP for iPhones, all went well. BUT...
If you (my customer) expects new mail, and opens his application, he starts to regularly press Send/Receive or Get mail button, to make new checks on servers. As to my notice, following checks take much longer time, than initial one after loading software, but then I noticed, that there is new mail on web client, but it can not be accessed via IMAP client. At least only possibility is to close email client, and after 5-6 minutes open it again. And then these new mails get synchronized. The same is with iPhone. When I resync account within a minute, phone is checking account, but no data get synchronized.
Is this connected with server tuning, as I suppose, that IMAP mail clients work corectly and there is no problem with network configuration and letancy?
If anybody experience similar things, please lead me to position to look for, as at the moment for me it is quite blank field. I do not notice any server (ZCS) overload at that time, and IMAP / POP is configured up to 1000 connections (which probably is too high for current needs).