diff --git a/spinnman/spalloc/session.py b/spinnman/spalloc/session.py
index 21fac6aba..ab3601705 100644
--- a/spinnman/spalloc/session.py
+++ b/spinnman/spalloc/session.py
@@ -262,7 +262,7 @@ def renew(self) -> JsonObject:
                         error = str(json_error)
                 except JSONDecodeError:
                     error = r.raw
-                raise KeyError(f"Unable to login: {error}") from e
+                raise SpallocException(f"Unable to login: {error}") from e
 
         # Step three: get the basic service data and new CSRF token
         obj: JsonObject = self.get(self.__srv_base).json()