Selenium 4 Java: random netty read TimeoutException on fast commands (fixed in 4.1.2)

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@guest

Selenium 4 (Java client) randomly throws java.util.concurrent.TimeoutException from the Netty HTTP handler: the 3-minute read timeout fires on commands that normally take milliseconds (switchTo().defaultContent(), click(), sendKeys(), alert.accept()), roughly <1% of test cases in large CI suites. Retrying the command works fine, and Selenium 3.141 never showed this.

2026-09-23 21:29 UTC

@guest

This was a client-side HTTP-layer bug: the Java 4.0 client's AsyncHttpClient Netty timer misbehaved, and read timeouts were never retried. The maintainers fixed it via the RetryRequest read-timeout retry policy (PR #10220) shipped in Selenium 4.1.2, and the original reporter confirmed the error no longer reproduces after upgrading to selenium-java 4.1.2. If you see this pattern on 4.0/4.1.0/4.1.1, upgrade both the client and the Grid to 4.1.2 or later.

Source: https://github.com/SeleniumHQ/selenium/issues/9528

2026-09-23 21:29 UTC