diff --git a/app/Services/SamlIdpService.php b/app/Services/SamlIdpService.php
index 98032b1..d879f41 100644
--- a/app/Services/SamlIdpService.php
+++ b/app/Services/SamlIdpService.php
@@ -255,6 +255,14 @@ public function generateResponse(
             $user->name,
         );
 
+        // emailaddress (Required by Microsoft SAML 2.0 specifications)
+        $this->addAttribute(
+            $dom,
+            $attributeStatement,
+            'http://schemas.xmlsoap.org/ws/2005/05/identity/claims/emailaddress',
+            $user->email,
+        );
+
         $assertion->appendChild($attributeStatement);
         $response->appendChild($assertion);
         $dom->appendChild($response);