I added the business account to Outlook (domain name and password) to Outlook 2011.
For the first time, all folders were synced just fine.
This is when some work is left unsaved to the Exchange mailbox from the OST files.
Having confirmed that the cause lies with synchronization (i.e.
that old data is being displayed in Microsoft Outlook), we advise reducing the size of the user's Sent Items folder and/or disabling Microsoft Outlook add-ins.
Due to this, Outlook can download all the items from Exchange Server again.
Below-written steps are to be followed: Suggestion: If the above-stated manual methods cannot fix Mac Outlook not syncing with Exchange server problem, then it is suggested that move from Mac Outlook to default email client application of Mac OS X i.e.
Outlook application synchronize OST file with Exchange Server mailbox when Exchange connectivity is there.
Synchronization speed can differ in different Outlook versions depending on the size of the data.
OST files, or if particular add-ins are installed in Microsoft Outlook.
Initially, you can confirm if the Sent Items Update has updated the sent item, or if Microsoft Outlook is displaying old data, by logging into the user’s mailbox using Outlook Web Access.
Apple Mail with an automated tool like OLM Converter for Mac.
Generally, Mac Outlook users face an issue regarding connectivity of the Exchange Server. The post explains multiple workaround solutions to fix Mac Outlook 2016 not syncing with the Exchange Server.
However, many Outlook users get error messages or face issues when the synchronization of their OST file (Offline Outlook Data File) fail.