Errors

What each error means and what to do next.

Every Servo error is a ServoError with code, message, and optional detail. Start from the named field or resource, because a retry does not fix an invalid input, a missing role, or an incompatible contract. Something that went wrong on the robot without an error starts from the report and the recording in First motion.

Errors by class

Error	When	Next step
Unauthorized	No sign-in, or an expired one	servo login; servo whoami says who you are
PermissionDenied	You hold no role, or a lower one, on that robot; the message names the role	Ask a robot admin for servo access grant
NotFound	A path, robot, deployment, or session does not exist	Check the name; for a private bucket, servo source verify
ActionSpaceIncompatible, EmbodimentUnsupported	The checkpoint does not match the robot type or its camera and state layout	Read report.reasons from model.inspect
ModelNotServable	Inspection found an unsupported model family or an incomplete export	Check the files; contact the Servo team with the path
ObservationInvalid	A camera role or the state is missing, wrongly shaped, or wrongly typed	The message names the role; check that camera with servo robot show
NotReady	The deployment is still loading	deployment.wait, or servo deployment wait
ServingDeadlineExceeded	One prediction missed its deadline	Check servo deployment show; retry only if another isolated prediction is still useful
ServingUnavailable, ServingCapacityExceeded	Capacity is gone or full	servo deployment list; wait, or stop what you no longer need
StaleGeneration	The deployment changed under an open session	Start a new session when the change is intended
PayloadTooLarge	An observation exceeded the request limit	Send frames as captured, with no extra channels; check the camera geometry with servo episode show

Read a hardware error

attach fails before any observation and names the role, the device it expected, and the condition, such as a camera that produced no frames.

Keep the request id

Around a prediction call, catch the error to keep its code and request id:

robot computer

import servo

sv = servo.Servo()
robot = sv.robots.attach("yam-cell-01")
deployment = sv.models.get("hf://allenai/MolmoAct2-BimanualYAM").deploy()
deployment.wait(timeout_s=900)
session = deployment.start(robot, instruction="pick up the red cup")

try:
    chunk = session.predict(robot)
except servo.ServoError as error:
    print(error.code, error.message, error.detail)
    raise

A network interruption raises a transport exception instead, and the absence of a response does not say whether the model ran. For support, keep the error code, the request id from detail, the deployment id, and the episode path.