Question about 'clean_session = false'

[NevainK]

I am having trouble using the clean_session=false .
For example, when a subscriber (clean_session=false) subscribes to a topic (QoS1), after it goes offline for some reason.
Another publisher publishes information to the topic (QoS1).
Then after the subscriber reconnects, it should be able to receive the previously published information.
But in fact the subscriber does not receive the information, and seems to have lost the previous subscription information.