Sometimes, Microsoft Outlook will not save an Exchange mailbox password even when the ‘Save Password’ option is selected.
This is usually caused by your computer being not joined to the same domain as the Exchange server. If your Exchange server was on-site, both your computer and the server would have the same domain, but with a hosted Exchange account, your Exchange server is on a different domain than your computer.
To match up your computer and your server:
*.outitgoes.com
*.exchange-outitgoes.com
											  Article ID: 245
											  Created On: Fri, Mar 13, 2015 at 11:42 AM
											  Last Updated On: Thu, Apr 23, 2015 at 11:40 AM
											  
											
Online URL: https://www.heartinternet.uk/support/article/why-won-t-outlook-save-my-exchange-mailbox-password.html