SmartThings Integration Stops Receiving Updates Intermittently

[Elad-Hanania]

The problem

The SmartThings integration in Home Assistant intermittently stops receiving updates from SmartThings, occurring approximately 1-2 times per day. When the issue happens, the state of SmartThings entities in Home Assistant becomes stale and does not reflect real-time changes.

Manually reloading the SmartThings integration via Settings -> Devices & Services -> SmartThings -> Reload temporarily resolves the issue, and updates resume until the next occurrence.

Please refer to the attached graph showing the power consumption of a refrigerator monitored via this integration. The periods where the graph line i

s flat clearly indicate when the data updates from SmartThings stopped arriving. The second arrow in each flat section points to the moment the integration was manually reloaded, after which the data stream resumed, as shown by the subsequent value changes.

Environment:

Home Assistant Core Version: HA 2025.3.3
Installation Type: Home Assistant Container
SmartThings Integration: Standard integration setup
External Access Configuration: Using Cloudflare Tunnel (running in a separate cloudflare/cloudflared container) to provide external access to the Home Assistant instance.

Log details (ERROR)

Logger: pysmartthings

Source: /usr/local/lib/python3.13/site-packages/pysmartthings/smartthings.py:475

First occurred: 08:21:41 (1 occurrences)

Last logged: 08:21:41

Error occurred while subscribing to eventsTraceback (most recent call last):

File "/usr/local/lib/python3.13/site-packages/aiohttp/client_proto.py", line 92, in connection_lost

uncompleted = self._parser.feed_eof()

File "aiohttp/_http_parser.pyx", line 508, in aiohttp._http_parser.HttpParser.feed_eof

aiohttp.http_exceptions.TransferEncodingError: 400, message:

Not enough data for satisfy transfer length header.

The above exception was the direct cause of the following exception:

Traceback (most recent call last):

File "/usr/local/lib/python3.13/site-packages/pysmartthings/smartthings.py", line 457, in subscribe

await self._internal_subscribe(session, subscription_url)

File "/usr/local/lib/python3.13/site-packages/pysmartthings/smartthings.py", line 379, in _internal_subscribe

async for event in event_source:

...<39 lines>...

break

File "/usr/local/lib/python3.13/site-packages/aiohttp_sse_client2/client.py", line 157, in anext

async for line_in_bytes in self._response.content:

...<21 lines>...

self._process_field(line, '')

File "/usr/local/lib/python3.13/site-packages/aiohttp/streams.py", line 52, in anext

rv = await self.read_func()

^^^^^^^^^^^^^^^^^^^^^^

File "/usr/local/lib/python3.13/site-packages/aiohttp/streams.py", line 352, in readline

return await self.readuntil()

^^^^^^^^^^^^^^^^^^^^^^

File "/usr/local/lib/python3.13/site-packages/aiohttp/streams.py", line 386, in readuntil

await self._wait("readuntil")

File "/usr/local/lib/python3.13/site-packages/aiohttp/streams.py", line 347, in _wait

await waiter

aiohttp.client_exceptions.ClientPayloadError: Response payload is not completed: <TransferEncodingError: 400, message='Not enough data for satisfy transfer length header.'>
Potential Cause / Observation:

---

Troubleshooting Steps Taken:

Confirmed regular occurrence of the issue (1-2 times daily).
Identified the specific error log entry.
Confirmed manual reload of the integration provides a temporary fix.
Reviewed Cloudflare settings (Security Insights), but could not find specific blocking events related to SmartThings in the available logs. Standard Cloudflare Tunnel setup is used to forward traffic to the Home Assistant container port 8123.

What version of Home Assistant Core has the issue?

core-2025.3.3

What was the last working version of Home Assistant Core?

No response

What type of installation are you running?

Home Assistant Container

Integration causing the issue

smartthings

Link to integration documentation on our website

https://www.home-assistant.io/integrations/smartthings

Diagnostics information

No response

Example YAML snippet

Anything in the logs that might be useful for us?

Logger: pysmartthings

Source: /usr/local/lib/python3.13/site-packages/pysmartthings/smartthings.py:475

First occurred: 08:21:41 (1 occurrences)

Last logged: 08:21:41

Error occurred while subscribing to eventsTraceback (most recent call last):

File "/usr/local/lib/python3.13/site-packages/aiohttp/client_proto.py", line 92, in connection_lost

uncompleted = self._parser.feed_eof()

File "aiohttp/_http_parser.pyx", line 508, in aiohttp._http_parser.HttpParser.feed_eof

aiohttp.http_exceptions.TransferEncodingError: 400, message:

Not enough data for satisfy transfer length header.

The above exception was the direct cause of the following exception:

Traceback (most recent call last):

File "/usr/local/lib/python3.13/site-packages/pysmartthings/smartthings.py", line 457, in subscribe

await self._internal_subscribe(session, subscription_url)

File "/usr/local/lib/python3.13/site-packages/pysmartthings/smartthings.py", line 379, in _internal_subscribe

async for event in event_source:

...<39 lines>...

break

File "/usr/local/lib/python3.13/site-packages/aiohttp_sse_client2/client.py", line 157, in __anext__

async for line_in_bytes in self._response.content:

...<21 lines>...

self._process_field(line, '')

File "/usr/local/lib/python3.13/site-packages/aiohttp/streams.py", line 52, in __anext__

rv = await self.read_func()

^^^^^^^^^^^^^^^^^^^^^^

File "/usr/local/lib/python3.13/site-packages/aiohttp/streams.py", line 352, in readline

return await self.readuntil()

^^^^^^^^^^^^^^^^^^^^^^

File "/usr/local/lib/python3.13/site-packages/aiohttp/streams.py", line 386, in readuntil

await self._wait("readuntil")

File "/usr/local/lib/python3.13/site-packages/aiohttp/streams.py", line 347, in _wait

await waiter

aiohttp.client_exceptions.ClientPayloadError: Response payload is not completed: <TransferEncodingError: 400, message='Not enough data for satisfy transfer length header.'>
Potential Cause / Observation:

Additional information

No response

[home-assistant]

Hey there @joostlek, mind taking a look at this issue as it has been labeled with an integration (smartthings) you are listed as a code owner for? Thanks!

Code owner commands

Code owners of smartthings can trigger bot actions by commenting:

• @home-assistant close Closes the issue.
• @home-assistant rename Awesome new title Renames the issue.
• @home-assistant reopen Reopen the issue.
• @home-assistant unassign smartthings Removes the current integration label and assignees on the issue, add the integration domain after the command.
• @home-assistant add-label needs-more-information Add a label (needs-more-information, problem in dependency, problem in custom component) to the issue.
• @home-assistant remove-label needs-more-information Remove a label (needs-more-information, problem in dependency, problem in custom component) on the issue.

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[joostlek]

Duplicate of #140426