robotframework / robotframework/SeleniumLibrary
Intermittent ReadTimeoutError (HTTPConnectionPool localhost) during long SeleniumLibrary execution with Chrome freezing
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Description
Hi,
We are experiencing intermittent ReadTimeoutError failures during long Robot Framework executions using SeleniumLibrary.
The issue is difficult to reproduce consistently, but it occurs frequently during large execution batches.
Environment
- Robot Framework: Robot Framework 7.3.2 (Python 3.12.0 on win32)
- SeleniumLibrary: 6.8.0
- Selenium: 4.36.0
- Chrome: 149.0.7827.200 (64-bit)
- Windows 11
Error
ReadTimeoutError:
HTTPConnectionPool(host='localhost', port=xxxxx):
Read timed out. (read timeout=120)
Sometimes we also see:
Timed out receiving message from renderer
Behavior
The browser visibly freezes when this happens.
The failure is intermittent and can occur in different Selenium keywords, for example:
- Click Element
- Wait Until Element Is Visible
- Wait Until Page Loaded
- Set Selenium Page Load Timeout
It most commonly happens during:
- Logout
- Navigating to the Browse module after switching back to the main window
However, it is not limited to those locations. The same timeout can occur in different tests at different steps.
Additional observations
- A new browser is launched for every test case.
- Failures are random and not tied to one specific test.
- The application is still running, but Chrome becomes unresponsive.
- Selenium waits for approximately 120 seconds before raising the ReadTimeoutError.
##Log excerpt
Wait Until Page Loaded 00:10:00.795KEYWORD 02_Browse_POM . Click On the Browse Module Start / End / Elapsed: | 20260706 15:04:20.439 / 20260706 15:14:21.234 / 00:10:00.795 -- | --Question
Has anyone experienced similar intermittent browser freezes resulting in HTTPConnectionPool(host='localhost') ReadTimeoutError?
Is this known to be related to SeleniumLibrary, Selenium Python, ChromeDriver, Chrome, or is there anything we should investigate further?
Any suggestions would be greatly appreciated.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Begin with the reported SeleniumLibrary keyword entry points—Click Element, Wait Until Element Is Visible, Wait Until Page Loaded, and Set Selenium Page Load Timeout—and reproduce under the listed versions. Compare the failing logout and Browse-module navigation with a minimal long-run case and collect Chrome/Selenium timeout logs; done means isolating a reproducible library failure or documenting that it is environmental or upstream.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- testing-qa
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Quiet
- Clarity
- Needs clarification
- Newbie friendliness
- 35/100