diff --git a/back/taiga_contrib_access_token_auth/services.py b/back/taiga_contrib_access_token_auth/services.py
index a43ca0b..bda5461 100644
--- a/back/taiga_contrib_access_token_auth/services.py
+++ b/back/taiga_contrib_access_token_auth/services.py
@@ -1,4 +1,5 @@
 import logging
+import os
 from django.db import transaction as tx
 from django.apps import apps
 from django.conf import settings
@@ -12,6 +13,13 @@
 
 USER_KEY = getattr(settings, "ACCESS_TOKEN_USER_KEY", "access_token_auth")
 
+def determine_role(groups):
+    if settings.GROUPS["OWNER"] in groups:
+        return settings.ROLES["OWNER"]
+    elif settings.GROUPS["ADMIN"] in groups:
+        return settings.ROLES["ADMIN"]
+    return settings.ROLES["MEMBER"]
+
 @tx.atomic
 def access_token_register(
         username: str,
@@ -21,78 +29,49 @@ def access_token_register(
         groups: list = None,
         token: str=None,
 ):
-    """
-    Register a new user from Access Token.
-
-    This can raise `exc.IntegrityError` exceptions in
-    case of conflicts found.
-
-    :returns: User
-    """
+    logger.info(f"Starting registration process for user: {email}")
     auth_data_model = apps.get_model("users", "AuthData")
     user_model = apps.get_model("users", "User")
+    membership_model = apps.get_model("projects", "Membership")
 
     try:
-        # Access Token user association exist?
-        auth_data = auth_data_model.objects.get(
-            key=USER_KEY,
-            value=oidc_guid,
-        )
+        auth_data = auth_data_model.objects.get(key=USER_KEY, value=oidc_guid)
         user = auth_data.user
+        logger.info(f"User already exists: {email}")
     except auth_data_model.DoesNotExist:
         try:
-            # Is a user with the same email as the Access Token user?
             user = user_model.objects.get(email=email)
-            auth_data_model.objects.create(
-                user=user,
-                key=USER_KEY,
-                value=oidc_guid,
-                extra={}
-            )
+            auth_data_model.objects.create(user=user, key=USER_KEY, value=oidc_guid, extra={})
+            logger.info(f"User found by email: {email}")
         except user_model.DoesNotExist:
-            # Create a new user
             username_unique = slugify(username)
-            user = user_model.objects.create(
-                email=email,
-                username=username_unique,
-                full_name=full_name,
-            )
-            auth_data_model.objects.create(
-                user=user,
-                key=USER_KEY,
-                value=oidc_guid,
-                extra={}
-            )
-
+            user = user_model.objects.create(email=email, username=username_unique, full_name=full_name)
+            auth_data_model.objects.create(user=user, key=USER_KEY, value=oidc_guid, extra={})
             send_register_email(user)
-            user_registered_signal.send(
-                sender=user.__class__,
-                user=user
-            )
+            user_registered_signal.send(sender=user.__class__, user=user)
+            logger.info(f"New user created: {email}")
 
     if token:
         membership = get_membership_by_token(token)
         membership.user = user
         membership.save(update_fields=["user"])
+        logger.info(f"Membership updated for user: {email}")
 
-    # Update user groups if provided
     if groups:
         user.groups.set(groups)
+        logger.info(f"Groups assigned to user: {email}, groups: {groups}")
+
+    default_role = determine_role(groups)
+    membership_model.objects.create(user=user, role=default_role)
+    logger.info(f"Role assigned to user: {email}, role: {default_role}")
 
     return user
 
 def access_token_login_func(request):
     try:
         access_token = request.POST['access_token']
-
         user_info = get_user_info(access_token)
-
-        # Маппинг групп и ролей
         groups = user_info.get('groups', [])
-        roles = []
-        for group in groups:
-            if group.startswith('role:'):
-                roles.append(group.split(':')[1])
 
         user = access_token_register(
             username=user_info['username'],
@@ -100,7 +79,6 @@ def access_token_login_func(request):
             full_name=user_info['full_name'],
             oidc_guid=user_info['guid'],
             groups=groups,
-            roles=roles,
         )
         data = make_auth_response_data(user)
         return data
@@ -112,4 +90,10 @@ def access_token_login_func(request):
         })
     except ConnectorBaseException as e:
         logger.error(f"Access Token authentication failed: {e.detail}")
-        raise e
\ No newline at end of file
+        raise e
+    except Exception as e:
+        logger.error(f"Unexpected error: {e}")
+        raise ConnectorBaseException({
+            "error_message": "Unexpected error",
+            "details": str(e)
+        })