Getting Timeout from Azure Service Bus

Question

Getting Timeout from Azure Service Bus

Carlos Sosa 5

I'm getting frequent TimeOut errors, from different locations a Twilio Function and an Azure Function.

These are long dumps from the Azure Function:

2025-10-02T16:40:43.398Z] Transport connection failed: TimeoutError('timed out')

[2025-10-02T16:40:43.401Z] AMQP error occurred: (AMQPConnectionError('Error condition: ErrorCondition.SocketError\n Error Description: Failed to initiate the connection due to exception: timed out')), condition: (<ErrorCondition.SocketError: b'amqp:socket-error'>), description: ('Failed to initiate the connection due to exception: timed out').

[2025-10-02T16:40:43.567Z] Link state changed: <LinkState.DETACHED: 0> -> <LinkState.ATTACH_SENT: 1>

[2025-10-02T16:40:44.998Z] 'servicebus.pysdk-508819a0' has an exception (ServiceBusConnectionError('Failed to initiate the connection due to exception: timed out Error condition: amqp:socket-error.')). Retrying.

Pashikanti Kumar 1,725 Reputation points Microsoft External Staff Moderator

2025-10-02T17:42:52.5+00:00

Hi Carlos Sosa,

Thank you for posting your question in the Microsoft Q&A forum

The timeout errors when connecting to Azure Service Bus from your Azure Functions and Twilio Function are fairly common and typically relate to network issues, client configuration, or Service Bus resource limits. Your logs showing AMQPConnectionError with timed out and socket errors confirm the connection attempts are failing.

Network Connectivity and Firewall

· Ensure outbound connectivity on TCP ports 5671 and 5672 (AMQP) is allowed from the function app hosting environment.

· If network restrictions apply, try switching Service Bus client to WebSocket transport which uses port 443, often open on restrictive networks.

Reference

Service Bus, Event Hubs, and Web Sockets | Microsoft Community Hub

Troubleshooting guide for Azure Service Bus - Azure Service Bus | Microsoft Learn

ServiceBusClientOptions interface | Microsoft Learn

Kindly let us know if the above helps or you need further assistance on this issue.

Please "Upvote" if the information helped you. This will help us and others in the community as well.

Thanks
Ram Ramakrishnan 15 Reputation points

2025-10-02T17:50:08.0233333+00:00

We are also having the same issue. A lot of timeout with occasional succesful connects. Nothing changed on our end. It started around 11:55 AM US EST. We opened a ticket with Microsoft and they are investigating.
Carlos Sosa 5 Reputation points

2025-10-02T17:50:32.4366667+00:00

But is something recently, from Twilio Function I'm also getting them:

Voice Status Error sending message: ServiceBusError: ETIMEDOUT: connect ETIMEDOUT 20.62.63.31:5671 at translateServiceBusError (/var/task/node_modules/@azure/service-bus/dist/index.js:647:16) at MessageSender.open (/var/task/node_modules/@azure/service-bus/dist/index.js:9158:37) at process.processTicksAndRejections (node:internal/process/task_queues:105:5) at async waitForTimeoutOrAbortOrResolve (/var/task/node_modules/@azure/service-bus/dist/index.js:1063:16) at async Object.sendEventPromise [as operation] (/var/task/node_modules/@azure/service-bus/dist/index.js:9083:21) at async Object.retry (/var/task/node_modules/@azure/core-amqp/dist/commonjs/retry.js:122:22) at async MessageSender.send (/var/task/node_modules/@azure/service-bus/dist/index.js:9197:20) at async Object.withSpan (/var/task/node_modules/@azure/core-tracing/dist/commonjs/tracingClient.js:36:28) { name: 'MessagingError', retryable: false, address: '20.62.63.31', code: 'GeneralError', errno: -110, port: 5671, syscall: 'connect' }

Is not every connections lets says for every 5 connections 3 fails.

Also, I see them in the Logs of my Function App:

And Function App runs inside Azure Network
Ram Ramakrishnan 15 Reputation points

2025-10-02T19:14:55.2033333+00:00

The Azure rep got back to us and updated us that they were noticing high CPU issues on the cluster that was hosting our service bus namespace. They are still working on it.
Pashikanti Kumar 1,725 Reputation points Microsoft External Staff Moderator

2025-10-02T19:54:28.87+00:00

@Ram Ramakrishnan could you please share you Microsoft Ticket Number.
EEP 0 Reputation points

2025-10-02T20:09:29.15+00:00

Hi @Pashikanti Kumar Our support request number is 2510020040007359 Thanks.
Pashikanti Kumar 1,725 Reputation points Microsoft External Staff Moderator

2025-10-02T20:17:06.16+00:00

Thanks for providing Support request number.
Carlos Sosa 5 Reputation points

2025-10-02T20:39:28.7866667+00:00

@Pashikanti Kumar It has to be something in Azure, as @Ram Ramakrishnan rep said they are having high CPU usage. Because I haven't changed anything on my side since yesterday and it was working flawless.
Carlos Sosa 5 Reputation points

2025-10-02T20:48:54.8466667+00:00

Going back in logs it started 9/30/2025 5:05 PM UTC

1 answer

Your answer

Pashikanti Kumar 1,725 Reputation points Microsoft External Staff Moderator

2025-10-02T17:42:52.5+00:00

Hi Carlos Sosa,

Thank you for posting your question in the Microsoft Q&A forum

The timeout errors when connecting to Azure Service Bus from your Azure Functions and Twilio Function are fairly common and typically relate to network issues, client configuration, or Service Bus resource limits. Your logs showing AMQPConnectionError with timed out and socket errors confirm the connection attempts are failing.

Network Connectivity and Firewall

· Ensure outbound connectivity on TCP ports 5671 and 5672 (AMQP) is allowed from the function app hosting environment.

· If network restrictions apply, try switching Service Bus client to WebSocket transport which uses port 443, often open on restrictive networks.

Reference

Service Bus, Event Hubs, and Web Sockets | Microsoft Community Hub

Troubleshooting guide for Azure Service Bus - Azure Service Bus | Microsoft Learn

ServiceBusClientOptions interface | Microsoft Learn

Kindly let us know if the above helps or you need further assistance on this issue.

Please "Upvote" if the information helped you. This will help us and others in the community as well.

Thanks
Ram Ramakrishnan 15 Reputation points

2025-10-02T17:50:08.0233333+00:00

We are also having the same issue. A lot of timeout with occasional succesful connects. Nothing changed on our end. It started around 11:55 AM US EST. We opened a ticket with Microsoft and they are investigating.
Carlos Sosa 5 Reputation points

2025-10-02T17:50:32.4366667+00:00

But is something recently, from Twilio Function I'm also getting them:

Voice Status Error sending message: ServiceBusError: ETIMEDOUT: connect ETIMEDOUT 20.62.63.31:5671 at translateServiceBusError (/var/task/node_modules/@azure/service-bus/dist/index.js:647:16) at MessageSender.open (/var/task/node_modules/@azure/service-bus/dist/index.js:9158:37) at process.processTicksAndRejections (node:internal/process/task_queues:105:5) at async waitForTimeoutOrAbortOrResolve (/var/task/node_modules/@azure/service-bus/dist/index.js:1063:16) at async Object.sendEventPromise [as operation] (/var/task/node_modules/@azure/service-bus/dist/index.js:9083:21) at async Object.retry (/var/task/node_modules/@azure/core-amqp/dist/commonjs/retry.js:122:22) at async MessageSender.send (/var/task/node_modules/@azure/service-bus/dist/index.js:9197:20) at async Object.withSpan (/var/task/node_modules/@azure/core-tracing/dist/commonjs/tracingClient.js:36:28) { name: 'MessagingError', retryable: false, address: '20.62.63.31', code: 'GeneralError', errno: -110, port: 5671, syscall: 'connect' }

Is not every connections lets says for every 5 connections 3 fails.

Also, I see them in the Logs of my Function App:

And Function App runs inside Azure Network
Ram Ramakrishnan 15 Reputation points

2025-10-02T19:14:55.2033333+00:00

The Azure rep got back to us and updated us that they were noticing high CPU issues on the cluster that was hosting our service bus namespace. They are still working on it.
Pashikanti Kumar 1,725 Reputation points Microsoft External Staff Moderator

2025-10-02T19:54:28.87+00:00

@Ram Ramakrishnan could you please share you Microsoft Ticket Number.
EEP 0 Reputation points

2025-10-02T20:09:29.15+00:00

Hi @Pashikanti Kumar Our support request number is 2510020040007359 Thanks.
Pashikanti Kumar 1,725 Reputation points Microsoft External Staff Moderator

2025-10-02T20:17:06.16+00:00

Thanks for providing Support request number.
Carlos Sosa 5 Reputation points

2025-10-02T20:39:28.7866667+00:00

@Pashikanti Kumar It has to be something in Azure, as @Ram Ramakrishnan rep said they are having high CPU usage. Because I haven't changed anything on my side since yesterday and it was working flawless.
Carlos Sosa 5 Reputation points

2025-10-02T20:48:54.8466667+00:00

Going back in logs it started 9/30/2025 5:05 PM UTC

Answer 1

Hi Carlos Sosa,

The timeout error log from your Twilio Function indicates this error

ServiceBusError: ETIMEDOUT: connect ETIMEDOUT 20.62.63.31:5671

This means the function was unable to establish a TCP connection to the Azure Service Bus IP address on port 5671 (the AMQP port) within the configured timeout.

Your Function App is running inside Azure network, which should typically have good outbound connectivity.
However, frequent connection timeouts (e.g., failing 3 out of 5 connections) usually indicate network reachability or firewall issues, or port blocking.
Port 5671 (AMQP) must be open outbound for the Azure Service Bus SDK to connect.
The error is a kernel-level TCP timeout (ETIMEDOUT) before establishing any SSL or AMQP communication.
This could be intermittent due to:
- Network Security Groups (NSGs) or Azure Firewall rules restricting outbound TCP on port 5671 intermittently.

Reference

Service Bus, Event Hubs, and Web Sockets | Microsoft Community Hub

Troubleshooting guide for Azure Service Bus - Azure Service Bus | Microsoft Learn

ServiceBusClientOptions interface | Microsoft Learn

Kindly let us know if the above helps or you need further assistance on this issue.

Please "Upvote" if the information helped you. This will help us and others in the community as well.

Thanks

Pravallika KV 2,845 Reputation points Microsoft External Staff Moderator

2025-10-15T10:35:36.2433333+00:00

Hi Carlos Sosa, following up to see if the above provided answer was helpful. If this answers your query, do click Accept Answer and Yes, if you have any further queries do let us know.

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Getting Timeout from Azure Service Bus

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