Microsoft have deprecated the use of basic authentication to bolster the security email accounts, this change by Microsoft requires an update to GuideConnect to support the Microsoft OAuth2 implementation
GuideConnect 1.23 and earlier do not support the modern authentication method required for OAuth.
Upgrade to GuideConnect 1.24 or later to use a Microsoft OAuth account. If you have GuideConnect 1.24 or later and experience issues with the email setup please contact email@example.com and supply the domain name for the email account you are having issues with.
More details on changes being implemented by Microsoft can be found here:
We recommend that you have a Premium plan with GuideConnect to ensure that you have access to the latest versions of the software for issues such as these, when changes occur that are out of our control.