@ancient-wolf-19325 hi we are getting below error in workflow tException: \\n\\nUser error.\" kind:USER]","ts":"2025-12-10T094103Z"} │ │ {"json":{"exec_id":"akkq7xvzx8658qgvv9kz","ns":"flyte-pipelines-production","res_ver":"616557977","routine":"worker-4","wf":"flyte-pipelinesproductionoptimization_engine_workflows.wf.main_wf"},"level":"debug │ │ ","msg":"Some downstream node has failed. Failed: [true]. TimedOut: [false]. Error: [code:\"USER:BadInputToAPI\" message:\"Traceback (most recent call last):\\n\\n File \\\"/usr/local/lib/python3.11/site │ │ -packages/flytekit/exceptions/scopes.py\\\", line 219, in user_entry_point\\n return wrapped(*args, **kwargs)\\n ^^^^^^^^^^^^^^^^^^^^^^^^\\n File \\\"/usr/local/lib/python3.11/site-pa │ │ ckages/flyte_common/on_failure_task.py\\\", line 77, in model_workflow_on_failure_task\\n return send_signal(execution_name, model_name, signal_value)\\n ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ │ │ ^^^^^^^^^^^^^^^^^^^\\n File \\\"/usr/local/lib/python3.11/site-packages/flyte_common/utils.py\\\", line 96, in send_signal\\n remote.set_signal(signal_name, execution_name, signal_value)\\n Fi │ │ le \\\"/usr/local/lib/python3.11/site-packages/flytekit/remote/remote.py\\\", line 524, in set_signal\\n self.client.set_signal(req)\\n File \\\"/usr/local/lib/python3.11/site-packages/flytekit/cli │ │ ents/raw.py\\\", line 159, in set_signal\\n return self._signal.SetSignal(signal_set_request, metadata=self._metadata)\\n ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ │ │ ^\\n File \\\"/usr/local/lib/python3.11/site-packages/grpc/_interceptor.py\\\", line 276, in __call__\\n response, ignored_call = self._with_call(\\n ^^^^^^^^^^^^^^^ │ │ ^\\n File \\\"/usr/local/lib/python3.11/site-packages/grpc/_interceptor.py\\\", line 328, in _with_call\\n call = self._interceptor.intercept_unary_unary(\\n ^^^^^^^^^^^^^^^^^^^^^^^^^ │ │ ^^^^^^^^^^^^^^^\\n File \\\"/usr/local/lib/python3.11/site-packages/flytekit/clients/grpc_utils/wrap_exception_interceptor.py\\\", line 44, in intercept_unary_unary\\n raise e\\n File \\\"/usr │ │ /local/lib/python3.11/site-packages/flytekit/clients/grpc_utils/wrap_exception_interceptor.py\\\", line 40, in intercept_unary_unary\\n self._raise_if_exc(request, e)\\n File \\\"/usr/local/lib/pyt │ │ hon3.11/site-packages/flytekit/clients/grpc_utils/wrap_exception_interceptor.py\\\", line 30, in _raise_if_exc\\n raise FlyteInvalidInputException(request) from e\\n\\nMessage:\\n\\n FlyteInvalidInpu │ │ tException: \\n\\nUser error.\" kind:USER]","ts":"2025-12-10T094116Z"}

The error

USER:BadInputToAPI

and

FlyteInvalidInputException

indicates that the workflow failed due to invalid input provided to the Flyte API, specifically when calling

set_signal

in your

send_signal

utility. This means the request to set a signal was malformed or missing required fields, causing Flyte to raise a user error and abort the node execution. According to the Flyte exception hierarchy,

FlyteInvalidInputException

is raised for bad or missing input to the API and is classified as a user error, not a system error (source, source). To resolve this, check the arguments passed to

remote.set_signal(signal_name, execution_name, signal_value)

and ensure all required fields are present and correctly formatted. The error is not due to Flyte system issues but rather incorrect usage of the API in your workflow code (source). Would you like more detail on how to debug or validate the signal input? Sources: - flytekit/exceptions/user.py - https://www.union.ai/docs/v2/flyte/_static/public/llms-full.txt 👍 0 button 👎 0 button 💡 Hint: Mention @runllm in the thread for followups.