Azure Service Bus SDK — .NET (C#)

Package: Azure.Messaging.ServiceBus | README | Full Troubleshooting Guide

Common Errors

Exception	Reason	Fix
`ServiceBusException` (ServiceTimeout)	Service didn't respond	Transient — auto-retried. For session accept, means no unlocked sessions
`ServiceBusException` (MessageLockLost)	Lock expired or link detached	Renew lock, reduce processing time, check network
`ServiceBusException` (SessionLockLost)	Session lock expired	Re-accept session, renew lock before expiry
`ServiceBusException` (QuotaExceeded)	Too many concurrent receives	Reduce receivers or use batch receives
`ServiceBusException` (MessageSizeExceeded)	Message or batch too large	Reduce payload. Premium tier supports individual messages up to 100MB. Batch limit is artificially computed on the client from the max message size sent by the service, so batches can also be impacted
`ServiceBusException` (ServiceBusy)	Request throttled	Auto-retried with 10s backoff. See throttling docs
`UnauthorizedAccessException`	Bad credentials	Verify connection string, SAS, or RBAC roles

try { /* receive messages */ }
catch (ServiceBusException ex) when (ex.Reason == ServiceBusFailureReason.ServiceTimeout)
{
    // Handle timeout
}

Socket exhaustion: Treat ServiceBusClient as singleton. Each creates a new AMQP connection. Always call CloseAsync/DisposeAsync.
Lock lost before expiry: Can happen on link detach (transient network) or 10-min idle timeout.
Processor high concurrency: May cause hangs with extreme concurrency settings. Test with moderate values.
Session processor slow switching: Tune SessionIdleTimeout to reduce wait time between sessions.
Batch size limits: Batch limit is artificially computed on the client from the max message size sent by the service. Send large messages individually if batch creation fails.
Transactions across entities: Requires all entities on same namespace. Use ServiceBusClient.CreateSender with via entity support.
WebSockets: Use ServiceBusTransportType.AmqpWebSockets when AMQP ports (5761, 5762) are blocked.

Package: Azure.Messaging.ServiceBus | README | Full Troubleshooting Guide

Exception	Reason	Fix
`ServiceBusException` (ServiceTimeout)	Service didn't respond	Transient — auto-retried. For session accept, means no unlocked sessions
`ServiceBusException` (MessageLockLost)	Lock expired or link detached	Renew lock, reduce processing time, check network
`ServiceBusException` (SessionLockLost)	Session lock expired	Re-accept session, renew lock before expiry
`ServiceBusException` (QuotaExceeded)	Too many concurrent receives	Reduce receivers or use batch receives
`ServiceBusException` (MessageSizeExceeded)	Message or batch too large	Reduce payload. Premium tier supports individual messages up to 100MB. Batch limit is artificially computed on the client from the max message size sent by the service, so batches can also be impacted
`ServiceBusException` (ServiceBusy)	Request throttled	Auto-retried with 10s backoff. See throttling docs
`UnauthorizedAccessException`	Bad credentials	Verify connection string, SAS, or RBAC roles

try { /* receive messages */ }
catch (ServiceBusException ex) when (ex.Reason == ServiceBusFailureReason.ServiceTimeout)
{
    // Handle timeout
}

Socket exhaustion: Treat ServiceBusClient as singleton. Each creates a new AMQP connection. Always call CloseAsync/DisposeAsync.
Lock lost before expiry: Can happen on link detach (transient network) or 10-min idle timeout.
Processor high concurrency: May cause hangs with extreme concurrency settings. Test with moderate values.
Session processor slow switching: Tune SessionIdleTimeout to reduce wait time between sessions.
Batch size limits: Batch limit is artificially computed on the client from the max message size sent by the service. Send large messages individually if batch creation fails.
Transactions across entities: Requires all entities on same namespace. Use ServiceBusClient.CreateSender with via entity support.
WebSockets: Use ServiceBusTransportType.AmqpWebSockets when AMQP ports (5761, 5762) are blocked.