This article provides you with information on how to resolve the common Outlook syncronization error.
If you see this popup on your Outlook it means that Outlook has not been set up to recognize that the server requires an Advanced IMAP configuration parameter put in place to properly read from the folder structure. This is called the IMAP Path Prefix
Note: this solution only works if the server you're connecting to uses IMAP as its mail server.
To fix this issue, open your account settings and head to the Advanced tab. At the very bottom of the window, you'll see an option entitled "Root folder path". Set this to INBOX in all capital letters. Click OK to apply the settings. You will now need to close Outlook entirely, then re-open the software for the change to take full effect.
Step 1. Click on Email Accounts
Step 2. Choose the Account, Either double click on the account or click on the account and click on change
Step 3. Click on More Settings
Step 4. Click on Advanced then type INBOX in the Root folder path field
If you find your mail folders have disappeared after making this change, simply revert the change and restart Outlook and your folders will return. You may need to restart your computer as sometimes Outlook doesn't fully close until you do so.