> ## Documentation Index
> Fetch the complete documentation index at: https://www.cometchat.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Troubleshooting

> Troubleshooting — CometChat documentation.

Common operational issues and debugging guidance.

## Common problems and likely causes

### 502 errors

* Possible cause: Chat API unreachable or unhealthy behind NGINX.
* Resolution:
  * Ensure the Chat API service is running: `docker service ps <chat-api-service>`
  * Check NGINX logs and upstream configuration to verify routing and upstream health.

### Kafka lag

* Possible cause: Consumer slowdown or insufficient partition count.
* Resolution:
  * Check Kafka consumer lag: `kafka-consumer-groups --describe --group <your-consumer-group> --bootstrap-server <kafka-broker>`
  * Increase partitions if needed: `kafka-topics --alter --partitions <new-partition-count> --topic <your-topic> --bootstrap-server <kafka-broker>`

### Redis eviction

* Possible cause: Memory pressure or incorrect eviction policy.
* Resolution:
  * Inspect memory settings: `redis-cli config get maxmemory` and `redis-cli config get maxmemory-policy`
  * Set an eviction policy such as `redis-cli config set maxmemory-policy allkeys-lru`

### TiKV region errors

* Possible cause: Disk latency, resource contention, or store imbalance.
* Resolution:
  * Check TiKV store status: `tiup cluster display`
  * Rebalance regions if needed: `tiup cluster restart <cluster-name> --force`

## Debugging commands

### Container and Swarm diagnostics

* View container logs: `docker logs <container-name>`
* Check service status: `docker service ps <service-name>`
* Inspect container details: `docker inspect <container-name>`

### TiDB cluster status

* Display cluster status with TiUP: `tiup cluster display <cluster-name>`