diff --git a/swh/auth/django/utils.py b/swh/auth/django/utils.py
--- a/swh/auth/django/utils.py
+++ b/swh/auth/django/utils.py
@@ -80,7 +80,8 @@
     user = oidc_user_from_decoded_token(decoded_token, client_id=oidc_client.client_id)
 
     # get authentication init datetime
-    auth_datetime = datetime.fromtimestamp(decoded_token["auth_time"])
+    auth_time = decoded_token.get("auth_time", decoded_token["iat"])
+    auth_datetime = datetime.fromtimestamp(auth_time)
     exp_datetime = datetime.fromtimestamp(decoded_token["exp"])
 
     # compute OIDC tokens expiration date
diff --git a/swh/auth/tests/test_utils.py b/swh/auth/tests/test_utils.py
--- a/swh/auth/tests/test_utils.py
+++ b/swh/auth/tests/test_utils.py
@@ -28,6 +28,7 @@
     decoded_token = copy(DECODED_TOKEN)
     decoded_token["groups"] = ["/staff", "api"]
     decoded_token["resource_access"] = {CLIENT_ID: {"roles": ["read-api"]}}
+    decoded_token.pop("auth_time")
 
     user = oidc_user_from_decoded_token(decoded_token, client_id=CLIENT_ID)