https://connect.mozilla.org/t5/discussions/firefox-148-datachannel-send-fails-with-invalidstateerror-after/m-p/119543#M46789 <P>WebRTC DataChannel worked perfectly in Firefox 147 and earlier, but after upgrading to Firefox 148, send() throws InvalidStateError immediately after onopen fires.</P><P>Same code works in Chrome and previous Firefox versions.</P><P class="lia-indent-padding-left-30px">const dataChannel = pc.createDataChannel('kvsDataChannel', { ordered: true, maxPacketLifeTime: 3000 }); dataChannel.onopen = () =&gt; { console.log('open, state:', dataChannel.readyState); // Shows "open" try { dataChannel.send('hello'); // Throws InvalidStateError } catch (e) { console.error('Failed:', e.name, e.message); } };</P><P>Error: InvalidStateError: An attempt was made to use an object that is not, or is no longer, usable</P><P>Environment: Firefox 148.0 Fails OS: Windows 11 Firefox 147 and earlier Works</P><P>Question: What changed in Firefox 148 that broke DataChannel send()? Any workaround while this gets fixed?</P> Mon, 09 Mar 2026 07:56:47 GMT Ethan26 2026-03-09T07:56:47Z https://connect.mozilla.org/t5/discussions/firefox-148-datachannel-send-fails-with-invalidstateerror-after/m-p/119543#M46789 <P>WebRTC DataChannel worked perfectly in Firefox 147 and earlier, but after upgrading to Firefox 148, send() throws InvalidStateError immediately after onopen fires.</P><P>Same code works in Chrome and previous Firefox versions.</P><P class="lia-indent-padding-left-30px">const dataChannel = pc.createDataChannel('kvsDataChannel', { ordered: true, maxPacketLifeTime: 3000 }); dataChannel.onopen = () =&gt; { console.log('open, state:', dataChannel.readyState); // Shows "open" try { dataChannel.send('hello'); // Throws InvalidStateError } catch (e) { console.error('Failed:', e.name, e.message); } };</P><P>Error: InvalidStateError: An attempt was made to use an object that is not, or is no longer, usable</P><P>Environment: Firefox 148.0 Fails OS: Windows 11 Firefox 147 and earlier Works</P><P>Question: What changed in Firefox 148 that broke DataChannel send()? Any workaround while this gets fixed?</P> Mon, 09 Mar 2026 07:56:47 GMT https://connect.mozilla.org/t5/discussions/firefox-148-datachannel-send-fails-with-invalidstateerror-after/m-p/119543#M46789 Ethan26 2026-03-09T07:56:47Z