Resolution:
This error indicates consumer configuration issue if the channel connecting to the EMS server is started, most likely it’s due to duplicated durable subscriptions.

When using EMS Topic as BE destination, the default DurableSubscriberName uses Global Variables “%%Deployment%%:%%EngineName%%:%%SessionName%%:%%ChannelURI%%:%%DestinationName%%”. This may result duplicated DurableSubscriberNames when deploying the same application in a deployment on multiple client machines within the same Admin domain as these service instances share the same deployment name and service instance name. The solution is to modify the default Service Instance Name when deploying on each Target Machine (e.g. Add machine name to the end of the default Service Instance Name), as the Service Instance Name is part of the Global Variable %%EngineName%%.

The duplicated DurableSubscriberNames also happen when deploying the same application in different Admin domains on the same machine. The solution is to modify the default DurableSubscriberName to add Global Variable %%Domain%% to it when configuring the EMS Topic destinations. i.e. “%%Domain%%:%%Deployment%%:%%EngineName%%:%%SessionName%%:%%ChannelURI%%:%%DestinationName%%”.