discordjs/discord.js · error · Error

No session available

Error message

No session available

What it means

setExternalSender() requires an active underlying MLS session; when this.session is null (not yet initialized), it throws 'No session available'. The MLS external sender payload can only be applied to an initialized session.

Source

Thrown at packages/voice/src/networking/DAVESession.ts:183

				this.session = new Davey.DAVESession(this.protocolVersion, this.userId, this.channelId);
				this.emit('debug', `Session initialized for protocol version ${this.protocolVersion}`);
			}

			this.emit('keyPackage', this.session!.getSerializedKeyPackage());
		} else if (this.session) {
			this.session.reset();
			this.session.setPassthroughMode(true, TRANSITION_EXPIRY);
			this.emit('debug', 'Session reset');
		}
	}

	/**
	 * Set the external sender for this session.
	 *
	 * @param externalSender - The external sender
	 */
	public setExternalSender(externalSender: Buffer) {
		if (!this.session) throw new Error('No session available');
		this.session.setExternalSender(externalSender);
		this.emit('debug', 'Set MLS external sender');
	}

	/**
	 * Prepare for a transition.
	 *
	 * @param data - The transition data
	 * @returns Whether we should signal to the voice server that we are ready
	 */
	public prepareTransition(data: VoiceDavePrepareTransitionData) {
		this.emit('debug', `Preparing for transition (${data.transition_id}, v${data.protocol_version})`);
		this.pendingTransitions.set(data.transition_id, data.protocol_version);

		// When the included transition id is 0, the transition is for (re)initialization and it can be executed immediately.
		if (data.transition_id === 0) {
			this.executeTransition(data.transition_id);
		} else {

View on GitHub (pinned to a81ed8a306)

Solutions

1. Ensure the session is initialized/ready before handling the external sender message
2. Buffer the external sender payload and apply it on session ready
3. Install/repair the @snazzah/davey dependency so initialization succeeds
4. Reinitialize the DAVE session and re-send the external sender

Example fix

// before
session.setExternalSender(payload);
// after
if (session.isReady()) session.setExternalSender(payload);
else pendingExternalSender = payload; // apply once ready

function canSetSender(s) { return (s as any).session != null; }
if (canSetSender(dave)) dave.setExternalSender(payload); else pendingSender = payload;

function hasActiveSession(s: { session?: unknown }): boolean { return s.session != null; }

try { dave.setExternalSender(buf); } catch (e) { if (e.message === 'No session available') pendingSender = buf; else throw e; }

When it happens

Trigger: Calling setExternalSender(buffer) (directly or via the binary websocket handler onWsBinary) before the DAVE session has finished initializing, or after it was destroyed.

Common situations: Voice gateway delivers the MLS external sender payload before session setup completes; session init failed due to a missing/incompatible @snazzah/davey install; race between gateway messages and session readiness.

Related errors

• Session not available
• Cannot destroy VoiceConnection - it has already been destroy
• ClientNotReady
• Session not available
• No compatible encryption modes. Available include: ${options

AI-assisted analysis of discordjs/discord.js@a81ed8a306 (2026-08-30). Data as JSON: /api/errors/9e0220e7f5135ee8. Report an issue: GitHub.