We had an application working on one system, and we moved it to another system, and we got MQ RC 2010 data length error. It turns out that the
SYSTEM.DEF.SVRCONN had MAXMSGL of 1 – so the maximum message sized allowed on this channel was 1 bytes.
You can specify the maximum msg length on the client for example the MQCD or client table – but I think the negotiation is the lower of the values at each end.
Setting the value to one on the z/OS end was part of stopping people using the default channel definitons.