Grok issue: "unable to reply" following Firefox 149.0 update

tgangale13 — Thu, 26 Mar 2026 14:12:45 GMT

Summary:
“Unable to reply” / stalled session state on grok.x.ai after recent Firefox update – occurs even in fresh sessions.Steps to Reproduce:

Update Firefox to the latest version (auto-update on 26 March 2026).
Open a new tab and navigate to grok.x.ai (or x.com/grok).
Start a new conversation or continue an existing one.
After a short period (typically within the first few messages or after a long response), the interface enters an “unable to reply” state.
Hard refresh (Ctrl+Shift+R), clearing cache/cookies for grok.x.ai and x.com, opening in Private Browsing mode, and disabling all extensions do not resolve the issue.

Expected Behavior:
Normal conversation flow with streaming responses.Actual Behavior:
Grok becomes unresponsive (“unable to reply”) and requires switching to another browser (Edge works reliably) or a full browser restart to recover.Additional Information:

Problem started immediately after the automatic Firefox update on 26 March 2026 ~9pm PDT.
Reproduced consistently in multiple fresh sessions/tabs.
No issues in Microsoft Edge on the same machine.
No relevant extensions active (tested with all disabled).
Occurs on both new and existing conversations.

Impact:
Completely breaks usability of Grok on Firefox. Workaround is to use Edge/Chrome.Suggested Priority: High (regression tied directly to recent Firefox release).

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Grok issue: "unable to reply" following Firefox 149.0 update