Local mqtt brokers started by mosquitto cannot be subscribed or published on it

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mosquitto: After running mqtt broker started locally for a few days, the client connected to it cannot post messages and subscribe messages. It seems that tcp connection can be established but it cannot interact with the mqtt protocol layer. Unfortunately, no log is saved. Has anyone been in a similar situation?
mosquitto Version: 2.0.18
Running platform: linux

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Sending messages on the broker using a mosquitto_pub connection will eventually result in an Error such as Error: Keepalive exceeded