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A few days ago, one of our clients faced an issue when using Zimbra Exchange ActiveSync (EAS) to sync emails on mobile or desktop devices. The issue occurs when email attachments are only partially downloaded. For example, a 14 MB attachment stops downloading at 7.4 MB, resulting in a corrupt or unusable file.
By default, Zimbra Exchange ActiveSync (EAS) limits the maximum size to 7 – 10 MB (10240000 Bytes). To increase the value, please run the following command
zmprov mcf zimbraMobileMaxMessageSize 102400000 zmmailboxdctl restart
In the above command, I simply added a 0 to the default value. Please adjust it according to your requirements.
Now, the client can download attachments larger than 10 MB from their mobile devices with EAS connection
Good Luck 🙂