Support / Troubleshooting / Microsoft Troubleshooting / Microsoft Authentication Troubleshooting Microsoft Authentication Troubleshooting As of October 1, 2022 Microsoft has deprecated Basic Authentication support for all Exchange Online accounts. Learn more through our Microsoft Exchange Online and Basic Auth Changes guide. Nylas Was Unable to Connect to the Exchange Server Couldn't Exchange OAuth Code for a Microsoft Refresh Token Exchange Autodiscovery Failed Incorrect Connection Settings Credential Errors Not Related to a Password Invalid Password Error Status 403 Unauthorized Error