Channel errors are why messages sit on transmission queues while dashboards show green queue managers. The queue manager is RUNNING; the path to the partner is not. Point-to-point SDR and RCVR pairs, cluster CLUSSDR and CLUSRCVR, and requester-server patterns all fail with recognizable CHSTATUS states, AMQ9208 family logs, and LASTCHLERR text—if you know the troubleshooting order. Beginners RESET CHANNEL repeatedly and wonder why RETRY returns. This encyclopedia page maps channel error categories: connectivity, security, sequence and recovery, capacity, and configuration mismatch. Use it with sender-channels, receiver-channels, and channel-states tutorials for attribute detail; use this page when the incident is messages not moving between queue managers.
INACTIVE means no active session—normal when idle, abnormal when work is expected. BINDING means TCP or TLS in progress. RUNNING means the channel transfers messages. RETRY means failure with automatic retry timers. STOPPED or STOPPING reflects operator STOP CHANNEL. A channel stuck in BINDING often indicates firewall, listener, or SSL hang. RETRY with repeating AMQERR lines indicates systematic misconfiguration. Capture DISPLAY CHSTATUS ALL on the sender queue manager first because XMITQ depth accumulates there.
| State | Meaning | Usual cause |
|---|---|---|
| INACTIVE | No session | Idle, not started, or failed and waiting |
| BINDING | Connecting | Network slow, SSL hang, listener delay |
| RUNNING | Transferring | Healthy path—or brief spike during batch |
| RETRY | Failed; will retry | CONNAME, TLS, CHLAUTH, sequence, partner down |
Connectivity failures happen before MQ channel protocol completes. Wrong CONNAME host or port is the most common beginner mistake—typo, DNS change, or load balancer pointing to wrong target. Listener not started on the receiver queue manager means connection refused. Firewall rules block return traffic in asymmetric setups. Verify with listener DISPLAY LSSTATUS and network telnet or openssl s_client to the port during a change window. Fix CONNAME and listener before touching MCAUSER.
12345DISPLAY CHSTATUS('PARIS.TO.LONDON') ALL DISPLAY LISTENER('TCP.LISTENER') STATUS DISPLAY CHANNEL('PARIS.TO.LONDON') CONNAME SSLCIPH * Partner must define same channel name as RCVR (or matching pair type) START CHANNEL('PARIS.TO.LONDON')
CHLAUTH can block a partner before RUNNING. AMQ8077 and AMQ9777 family messages name the rule. TLS may succeed while CHLAUTH still blocks if certificate mapping does not match. Align SSLPEER rules, ADDRESSMAP, and USERMAP records with change control. After intentional block, document the rule ID so future engineers do not remove the wrong record.
After restore or DR failover, one side may hold a higher sequence number than the partner expects. Channels fail with sequence-related LASTCHLERR and AMQ9513-class messages. Fix requires coordinated RESET CHANNEL on both sides after leadership agrees which queue manager is authoritative. Never reset only one end in production without partner approval—duplicate delivery or lost messages risk follows.
Messages larger than channel MAXMSGL fail transfer with reason tied to message size. Both channel ends need compatible MAXMSGL at least as large as the message and queue MAXMSGL. MQRC 2071 MSG_TOO_BIG_FOR_CHANNEL in applications points here. ALTER CHANNEL on both sides and restart or trigger channel refresh per platform behavior.
| Category | Symptom | First fix |
|---|---|---|
| Connectivity | RETRY, connection refused | CONNAME, listener, firewall |
| SSL | RETRY, AMQ9638 | SSLCIPH, certs—see SSL encyclopedia |
| CHLAUTH | BINDING fail, AMQ8077 | Named CHLAUTH rule |
| Sequence | RETRY after DR | Coordinated RESET CHANNEL |
| Capacity | Intermittent transfer fail | MAXMSGL alignment |
Cluster channels add repository exchange. A stuck CLUSSDR to the full repository blocks catalog updates. Symptoms include cluster puts routing wrong and auto-defined channels in perpetual RETRY. Use DISPLAY CLUSQMGR, REFRESH CLUSTER, and repository role knowledge. Point-to-point fixes applied blindly to cluster channels can worsen repository inconsistency.
While SDR is in RETRY, PUTs to routes using the transmission queue still enqueue unless the application handles failures. Monitor CURDEPTH and MAXDEPTH on XMITQ. Alert before full to avoid 2053 on upstream. Consider pausing batch feeds during prolonged partner outage. After channel RUNNING, depth drains at channel throughput—plan catch-up capacity.
Queues are warehouses in each city. The channel is the truck route. Errors are roadblocks—wrong address, closed gate, expired toll pass, or mismatched manifests after a warehouse rebuild—not problems inside the warehouse shelves themselves.
Two toy cities send trucks on a road. If the bridge is closed or the keys do not match, trucks wait in a parking lot (XMITQ) until the road works again.
Break CONNAME in lab; document CHSTATUS, AMQ9208, and XMITQ depth.
Write runbook row for RETRY with SSL versus RETRY with connection refused.
List data to collect before calling partner operations.
1. AMQ9208 commonly relates to:
2. SDR channel needs:
3. Channel names for SDR/RCVR pair must:
4. FIRST check on RETRY is often: