FAQ > Errors > Exceptions > javax.jms.JMSException - Wire format negociation timeout - peer did not send his wire format.

If you get exception like this:

javax.jms.JMSException: Wire format negociation timeout: peer did not send his wire format.
    at org.apache.activemq.util.JMSExceptionSupport.create(JMSExceptionSupport.java:58)
    at org.apache.activemq.ActiveMQConnection.syncSendPacket(ActiveMQConnection.java:1185)
    at org.apache.activemq.ActiveMQConnection.ensureConnectionInfoSent(ActiveMQConnection.java:1263)
    at org.apache.activemq.ActiveMQConnection.start(ActiveMQConnection.java:449)

it can mean one of three things:

1. You’re connecting to the port not used by ActiveMQ Classic TCP transport

Make sure to check that you’re connecting to the appropriate host:port

1. You’re using log4j JMS appender and doesn’t filter out ActiveMQ Classic log messages

Be sure to read How do I use log4j JMS appender with ActiveMQ Classic and more importantly to never send ActiveMQ Classic log messages to JMS appender

1. Your broker is probably under heavy load (or network connection is unreliable), so connection setup cannot be completed in a reasonable time

If you experience sporadic exceptions like this, the best solution is to use failover transport, so that your clients can try connecting again if the first attempt fails. If you’re getting these kind of exceptions more frequently you can also try extending wire format negotiation period (default 10 sec). You can do that by using wireFormat.maxInactivityDurationInitalDelay property on the connection URL in your client. For example

tcp://localhost:61616?wireFormat.maxInactivityDurationInitalDelay=30000

will use 30 sec timeout.