Troubleshooting¶

Authentication required¶

AuthenticationError: Authentication required. Provide a token or
client_id+client_secret (or OPENQUANTUM_TOKEN / OPENQUANTUM_CLIENT_ID +
OPENQUANTUM_CLIENT_SECRET / OPENQUANTUM_SDK_KEY).

No credentials were found. OpenQuantumBackend calls OpenQuantumService.from_env(). Set OPENQUANTUM_CLIENT_ID and OPENQUANTUM_CLIENT_SECRET, set OPENQUANTUM_TOKEN or OPENQUANTUM_SDK_KEY, or pass token=, client_id= + client_secret=, or a pre-built service=. See Authentication.

`configuration_data validation failed: ... required property 'engine'`¶

The target backend requires extra configuration that was not supplied. The Quantum Rings simulator, for example, requires an engine:

oq = OpenQuantumBackend(
    backend="qr:gpu-gb10",
    shots=1024,
    configuration_data={"engine": "amber_quantum_rings"},
)

`configuration_data validation failed: ... must match "else" schema`¶

A backend's configuration schema can be conditional. The Quantum Rings simulator only permits threshold when performance="CUSTOM". Send such fields only when they apply:

# Valid: no threshold unless performance is CUSTOM
configuration_data={"engine": "amber_quantum_rings"}

# Valid: threshold allowed because performance is CUSTOM
configuration_data={"engine": "amber_quantum_rings", "performance": "CUSTOM", "threshold": 128}

`QASM precompilation failed: At most one qubit register allowed`¶

This should not occur: the plugin flattens Qrisp's per-qubit registers onto a single register automatically. If you see it, make sure you are on a current version of openquantum-sdk[qrisp] and are submitting through get_measurement / run (not a hand-built payload).

Results look bit-reversed¶

The platform returns bitstrings in Qiskit's little-endian convention (the first classical bit is the rightmost character). Qrisp reconciles bit order during measurement decoding, so the default (reverse_bits=False) is correct. If a particular backend instead returns counts big-endian, construct the backend with reverse_bits=True. Confirm with an asymmetric state such as |01>.

Shots are required¶

Open Quantum is shot-based; analytic execution is not supported. Set shots on the backend or pass shots= to get_measurement / run.

Backend is offline or not accepting jobs¶

Pick another backend. List what is online with the Core SDK (client.backends(online=True)), the Qiskit plugin, or the Open Quantum Portal.

Organization could not be resolved¶

If your account belongs to more than one organization, pass an explicit organization_id to the backend (discover it via client.organizations()).