Why do I get a Microsoft Teams authentication error in Vtiger CRM?

This issue typically occurs when Vtiger CRM is unable to connect to Microsoft Teams due to token or permission problems. Common causes include:

• Expired Access Token – The OAuth token granted during the initial Microsoft Teams authentication has expired.
• Revoked Permissions – The user or admin has revoked the app’s access from their Microsoft account.
• Password Changed – If the password for the linked Microsoft account has been changed, the stored token becomes invalid.
• Consent Removed from Microsoft Tenant – The Microsoft admin may have removed app permissions or updated security policies that impact the app's access.
• CRM Token Cache Issue – The token stored in Vtiger’s sync settings may be corrupted due to session mismatches or other system-level issues.