Workers cannot connect to workpool #20750
Description
Bug summary
I am trying to host a work pool on a Fedora 42 host and then have a Windows workers connect to the work pool and service a deployment made on that work pool. The deployment creation works but when I run prefect worker start --pool "local-pool" to deploy my workers, I am getting an error saying that the websocket couldnt be made even though the logs indicate a websocket connection was made.
Specifically I am seeing the following
14:14:28.662 | DEBUG | prefect.client - Connecting to API at http://192.168.71.26:4200/api/
14:14:28.664 | DEBUG | prefect.events.clients - Reconnecting websocket connection.
14:14:28.665 | DEBUG | prefect.events.clients - Opening websocket connection.
14:14:28.673 | DEBUG | prefect.events.clients - Pinging to ensure websocket connected.
14:14:28.675 | DEBUG | prefect.events.clients - Pong received. Websocket connected.
14:14:28.676 | DEBUG | prefect.events.clients - Authenticating...
14:14:28.682 | WARNING | prefect.events.clients - Unable to connect to 'ws://192.168.71.26:4200/api/events/in'. Please check your network settings to ensure websocket connections to the API are allowed. Otherwise event data (including task run data) may be lost. Reason: Unable to authenticate to the event stream. Please ensure the provided auth_token you are using is valid for this environment. . Set PREFECT_DEBUG_MODE=1 to see the full error.
Version info
The Prefect server:
S:/$ prefect version
22:53:38.993 | DEBUG | prefect.profiles - Using profile 'debug-testing'
Version: 3.4.25
API version: 0.8.4
Python version: 3.9.25
Git commit: 8a37e7b1
Built: Thu, Oct 23, 2025 07:58 PM
OS/Arch: linux/x86_64
Profile: debug-testing
Server type: server
Pydantic version: 2.12.5
Server:
Database: sqlite
SQLite version: 3.34.1
Integrations:
prefect-github: 0.3.2
The Windows worker:
S:\>prefect version
14:53:47.047 | DEBUG | prefect.profiles - Using profile 'debug-testing'
Version: 3.6.16
API version: 0.8.4
Python version: 3.13.10
Git commit: e7d587cd
Built: Thu, Feb 05, 2026 07:37 PM
OS/Arch: win32/AMD64
Profile: debug-testing
Server type: server
Pydantic version: 2.12.4
Server:
Database: sqlite
SQLite version: 3.51.0
Integrations:
prefect-github: 0.4.1
Additional context
I have a server set up with the profile given by
S:/$ prefect profile inspect
22:49:08.962 | DEBUG | prefect.profiles - Using profile 'debug-testing'
No name provided, defaulting to 'debug-testing'
PREFECT_SERVER_ALLOW_EPHEMERAL_MODE='true'
PREFECT_API_URL='http://0.0.0.0:4200/api'
PREFECT_RESULTS_PERSIST_BY_DEFAULT='true'
PREFECT_LOGGING_LEVEL='DEBUG'
And my code is hosted on a private github repo, so I am creating my deployment with the following:
from prefect import flow, task
...
if __name__ == "__main__":
github_repo = GitRepository(
url="https://github.com/user/repo",
credentials=GitHubCredentials.load("token"),
)
flow.from_source(
source=github_repo,
entrypoint="src/workflows/flows/file.py:my_flow",
).deploy(
name="my_flow",
work_pool_name="local-pool",
)
and the token is made in advance with the following, where TOKEN is a fine-grained token from Github with all required permissions.
github_credentials_block = GitHubCredentials(token=TOKEN)
github_credentials_block.save(name="token", overwrite=True)
All of the above allows the prefect server to successfuly create a deployment and make it available through the web GUI.
For my windows workers, I have a simple profile given by
(prefect) S:\>prefect profile inspect
14:48:08.581 | DEBUG | prefect.profiles - Using profile 'debug-testing'
No name provided, defaulting to 'debug-testing'
PREFECT_API_URL='http://192.168.71.26:4200/api'
PREFECT_LOGGING_LEVEL='DEBUG'
And I am simply running prefect worker start --pool "local-pool" to start the worker and make it service the work pool but it fails to start with this log.