diff --git a/sdk/python/scilog/scicat.py b/sdk/python/scilog/scicat.py
index 5e2c8577..8b112430 100644
--- a/sdk/python/scilog/scicat.py
+++ b/sdk/python/scilog/scicat.py
@@ -6,7 +6,7 @@ class SciCatRestAPI(HttpClient):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.login_path = self._login_path or "https://dacat.psi.ch/auth/msad"
-        self.token_prefix = self.options.get("token_prefix", "")
+        self.token_prefix = self.options.get("token_prefix", "") or ""
 
     def authenticate(self, username, password):
         auth_payload = {"username": username, "password": password}
diff --git a/sdk/python/tests/test_scicat.py b/sdk/python/tests/test_scicat.py
index e9a84bce..a1566554 100644
--- a/sdk/python/tests/test_scicat.py
+++ b/sdk/python/tests/test_scicat.py
@@ -11,6 +11,7 @@
     "token_prefix",
     [
         "",
+        None,
         "Bearer ",
     ],
 )
@@ -41,7 +42,7 @@ def test_get_proposals(mock_post, mock_get, token_prefix):
     mock_post.assert_called_with(
         f"{address}/proposals",
         params=None,
-        headers={**headers, "Authorization": f"{token_prefix}{token}"},
+        headers={**headers, "Authorization": f"{token_prefix or ''}{token}"},
         timeout=ANY,
         verify=True,
     )