While troubleshooting Event Hub issue with MS Support, Service Bus Explorer was used.
Problem statement: Unable to create a consumer group listener in Service Bus Explorer with the following error message:
InnerException: An error occurred during communication with 'N/A'. Check the connection information, then retry.

Action Done:

We used a namespace-level connection string and confirmed that we could retrieve event hub entities and create a new consumer group in Service Bus Explorer without any issues. However, when trying to create a consumer group listener to fetch messages, the operation failed with the error message described above. We verified that network connectivity is working properly and that the local PC can connect to the service bus server via port 5671.

Version: 5.0.18

Next Action:
Need to raise a GitHub issue since it's an open source tool.