diff --git a/lib/services/microsoft-calendar-sync.ts b/lib/services/microsoft-calendar-sync.ts
index 9cbf96e..d10c0ae 100644
--- a/lib/services/microsoft-calendar-sync.ts
+++ b/lib/services/microsoft-calendar-sync.ts
@@ -435,6 +435,10 @@ export async function updateMicrosoftEvent(
       eventId,
     });
   } catch (error: any) {
+    // Check if it's a permissions error (403) - likely missing Calendars.ReadWrite scope
+    const isPermissionError = error.response?.status === 403;
+    const errorCode = error.response?.data?.error?.code;
+    
     logger.error('Error updating Microsoft event', {
       userId,
       email,
@@ -443,6 +447,11 @@ export async function updateMicrosoftEvent(
       error: error instanceof Error ? error.message : String(error),
       responseStatus: error.response?.status,
       responseData: error.response?.data,
+      isPermissionError,
+      errorCode,
+      suggestion: isPermissionError 
+        ? 'Token likely missing Calendars.ReadWrite scope. User needs to re-authenticate the Microsoft account in Courrier page to get new permissions.'
+        : undefined,
     });
     throw error;
   }
@@ -483,6 +492,10 @@ export async function deleteMicrosoftEvent(
       eventId,
     });
   } catch (error: any) {
+    // Check if it's a permissions error (403) - likely missing Calendars.ReadWrite scope
+    const isPermissionError = error.response?.status === 403;
+    const errorCode = error.response?.data?.error?.code;
+    
     logger.error('Error deleting Microsoft event', {
       userId,
       email,
@@ -491,6 +504,11 @@ export async function deleteMicrosoftEvent(
       error: error instanceof Error ? error.message : String(error),
       responseStatus: error.response?.status,
       responseData: error.response?.data,
+      isPermissionError,
+      errorCode,
+      suggestion: isPermissionError 
+        ? 'Token likely missing Calendars.ReadWrite scope. User needs to re-authenticate the Microsoft account in Courrier page to get new permissions.'
+        : undefined,
     });
     throw error;
   }