diff --git a/auth_server/auth.py b/auth_server/auth.py
index 3f31cc2..fc48fd8 100644
--- a/auth_server/auth.py
+++ b/auth_server/auth.py
@@ -82,7 +82,6 @@ def create_access_token(
 
 def db_auth(session: Session, username: str, password: str) -> schema.User | None:
     """Authenticates user based on username and password
-
     User data is read from database.
     """
     logger.info(f"Database based authentication for '{username}'")
@@ -127,7 +126,6 @@ async def ldap_auth(
 
     return dbapi.get_or_create_user_by_email(session, email)
 
-
 async def oidc_auth(
     session: Session, client_id: str, code: str, redirect_url: str
 ) -> str | None:
@@ -141,6 +139,8 @@ async def oidc_auth(
         client_id=client_id,
         code=code,
         redirect_url=redirect_url,
+        scope=settings.papermerge__auth__oidc_scope,
+        tenant_id=settings.papermerge__auth__oidc_tenant_id,
     )
 
     logger.debug("Auth:oidc: sign in")
@@ -156,7 +156,6 @@ async def oidc_auth(
 
     return result
 
-
 def create_token(user: schema.User) -> str:
     access_token_expires = timedelta(
         minutes=settings.papermerge__security__token_expire_minutes
@@ -175,4 +174,4 @@ def create_token(user: schema.User) -> str:
         algorithm=settings.papermerge__security__token_algorithm,
     )
 
-    return access_token
+    return access_token
\ No newline at end of file
diff --git a/auth_server/backends/oidc.py b/auth_server/backends/oidc.py
index cbe6ac5..9895596 100644
--- a/auth_server/backends/oidc.py
+++ b/auth_server/backends/oidc.py
@@ -7,8 +7,6 @@
 
 class OIDCAuth:
     name: str = 'oidc'
-    # provider_url: str = 'https://oauth2.googleapis.com/token'
-    # userinfo_url: str = 'https://www.googleapis.com/oauth2/v3/userinfo'
     access_token: str | None = None
 
     def __init__(
@@ -18,7 +16,9 @@ def __init__(
         client_secret: str,
         client_id: str,
         code: str,
-        redirect_url: str
+        redirect_url: str,
+        scope: str | None = None,
+        tenant_id: str | None = None
     ):
         self.access_token_url = access_token_url
         self.user_info_url = user_info_url
@@ -26,24 +26,29 @@ def __init__(
         self.client_id = client_id
         self.code = code
         self.redirect_url = redirect_url
+        self.scope = scope or "openid profile email"
+        self.tenant_id = tenant_id
 
     async def signin(self):
         async with httpx.AsyncClient() as client:
-            params = {
+            # Entra ID requires credentials in the request body as form data
+            # not as URL parameters
+            data = {
                 'grant_type': 'authorization_code',
                 'client_id': self.client_id,
                 'client_secret': self.client_secret,
-                # do we need this param?
                 'redirect_uri': self.redirect_url,
                 'code': self.code,
+                'scope': self.scope,
             }
-            logger.debug(f"oidc signin params: {params}")
+            
+            logger.debug(f"oidc signin with client_id: {self.client_id}")
+            logger.debug(f"oidc signin url: {self.access_token_url}")
 
             try:
                 response = await client.post(
                     self.access_token_url,
-                    params=params,
-                    data=params,
+                    data=data,
                     headers={'Content-Type': 'application/x-www-form-urlencoded'}
                 )
             except Exception as ex:
@@ -62,7 +67,12 @@ async def signin(self):
                 ])
                 raise ValueError(message)
 
-            self.access_token = response.json()['access_token']
+            response_data = response.json()
+            self.access_token = response_data.get('access_token')
+            
+            if not self.access_token:
+                raise ValueError("No access_token in response")
+                
             return self.access_token
 
     async def user_email(self):
@@ -88,7 +98,21 @@ async def user_email(self):
                 ])
                 raise ValueError(message)
 
-            return response.json()['email']
+            user_info = response.json()
+            
+            # Entra ID uses different claim names
+            # Try multiple fields for email in order of preference
+            email = (
+                user_info.get('email') or 
+                user_info.get('preferred_username') or 
+                user_info.get('upn') or
+                user_info.get('unique_name')
+            )
+            
+            if not email:
+                raise ValueError(f"No email found in user info response: {user_info}")
+                
+            return email
 
 
 async def introspect_token(
@@ -105,7 +129,7 @@ async def introspect_token(
     """
     ret_value = False
     async with httpx.AsyncClient() as client:
-        params = {
+        data = {
             'token': token,
             'client_id': client_id,
             'client_secret': client_secret,
@@ -114,8 +138,7 @@ async def introspect_token(
         try:
             response = await client.post(
                 url,
-                params=params,
-                data=params,
+                data=data,
                 headers={'Content-Type': 'application/x-www-form-urlencoded'}
             )
         except Exception as ex:
@@ -129,6 +152,6 @@ async def introspect_token(
             ])
             raise ValueError(message)
 
-        ret_value = response.json()['active']
+        ret_value = response.json().get('active', False)
 
     return ret_value
diff --git a/auth_server/config.py b/auth_server/config.py
index 6d59064..97fee00 100644
--- a/auth_server/config.py
+++ b/auth_server/config.py
@@ -35,6 +35,9 @@ class Settings(BaseSettings):
     papermerge__auth__oidc_user_info_url: str | None = None
     # https://datatracker.ietf.org/doc/html/rfc7662
     papermerge__auth__oidc_introspect_url: str | None = None
+    # Entra ID specific settings
+    papermerge__auth__oidc_tenant_id: str | None = None
+    papermerge__auth__oidc_scope: str | None = None
 
     papermerge__auth__ldap_url: str | None = None  # e.g. ldap.trusel.net
     papermerge__auth__ldap_use_ssl: bool = True
@@ -49,4 +52,4 @@ class Settings(BaseSettings):
 
 @lru_cache()
 def get_settings():
-    return Settings()
+    return Settings()
\ No newline at end of file