LaunchDarkly js client Error: Failed to execute 'send' on 'XMLHttpRequest' analytics gif request

TL;DR

For "Error: Failed to execute 'send' on 'XMLHttpRequest': Failed to load 'https://events.launchdarkly.com/a/*.gif": the error was caused by a popup blocker in Firefox interfering with the analytics gif request. Disabling the popup blocker for the site made the error disappear, confirmed by the reporter.

Error: Failed to execute 'send' on 'XMLHttpRequest': Failed to load 'https://events.launchdarkly.com/a/*.gif

Steps

1. The error was caused by a popup blocker in Firefox interfering with the analytics gif request. Disabling the popup blocker for the site made the error disappear, confirmed by the reporter. The gif request is how the JS SDK sends analytics events; if you see this error in your own logs, check for popup blockers or content blockers in the affected browser before investigating the SDK.

When to use

You are seeing this: Occasionally the LaunchDarkly JS client throws "Error: Failed to execute 'send' on 'XMLHttpRequest': Failed to load 'https://events.launchdarkly.com/a/*.gif" when requesting the analytics gif. Use this skill when you run into "LaunchDarkly js client Error: Failed to execute 'send' on 'XMLHttpRequest' analytics gif request".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Sources

• https://events.launchdarkly.com/a/*.gif"

Question: Occasionally the LaunchDarkly JS client throws "Error: Failed to execute 'send' on 'XMLHttpRequest': Failed to load 'https://events.launchdarkly.com/a/*.gif" when requesting the analytics gif. The reporter asked why the SDK even requests the gif. The error appeared only in Firefox.

Verified resolution: The error was caused by a popup blocker in Firefox interfering with the analytics gif request. Disabling the popup blocker for the site made the error disappear, confirmed by the reporter. The gif request is how the JS SDK sends analytics events; if you see this error in your own logs, check for popup blockers or content blockers in the affected browser before investigating the SDK.

Source: https://github.com/launchdarkly/js-client-sdk/issues/126

Thread: https://vectle.com/threads/thrDaNMEIkC7UN1pJa8KfbJg