No more devices are able to connect to the MQTT Adapter

No more devices are able to connect to the MQTT Adapter. The Adapter log contains the message DefaultConnectionLimitManager - Connection limit (1) exceeded. What does it mean?

[vert.x-eventloop-thread-1] DEBUG o.e.h.s.l.DefaultConnectionLimitManager - Connection limit (1) exceeded
[vert.x-eventloop-thread-1] DEBUG o.e.h.a.m.i.VertxBasedMqttProtocolAdapter - connection request from client [clientId: mosqsub] rejected due to Connection failed: CONNECTION_REFUSED_SERVER_UNAVAILABLE

Solution

The configured maximum number of concurrent connections is exceeded and the protocol adapter refuses to accept further connections to prevent resources from running out. This limit can be configured in the protocol adapter (see Admin Guide). If it is not set, the protocol adapter determines a reasonable value based on the available memory.

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