Fixing "Error... Error 400: Error Parsing Token"

Created by Daniel Calkin, Modified on Mon, 31 Mar at 5:37 PM by Daniel Calkin

Problem

A red box is displayed in the Verisend Pro application stating: "Error Sorry there was an error with your request. Error 400: Error parsing token. Please try again." when a user attempt to view scan results or change their user preferences. This is displayed when using their Outlook client and/or when viewing messages using Outlook on the Web (OWA). However, for users with background scanning enabled, messages still get tagged with Verisend categories and Spam messages are moved to the Junk folder.

Additional Information

Microsoft deprecated one of the authentication technologies used by Verisend user interface common to both the Outlook and OWA interfaces but gives M365 tenant administrators the option to keep using it. More information here:

https://learn.microsoft.com/en-us/office/dev/add-ins/outlook/faq-nested-app-auth-outlook-legacy-tokens#what-is-the-timeline-for-shutting-down-legacy-exchange-online-tokens

Solution

Run the following Powershell command using Exchange Online Remote PowerShell connected to your Microsoft 365 tenant.

Set-AuthenticationPolicy -Identity LegacyExchangeTokens -AllowLegacyExchangeTokens