Can not access API via device

Question

Can not access API via device

DJ 70

Hi

For security purposes, i do not wish to place my API links on here, but today about 4am UK time, my device could not connect to any API, can you please advice me or help me via screen share session to resolve this issue?
I am getting 701 errors. This is urgent

DJ 70 Reputation points

2025-04-01T11:16:34.64+00:00

Can it be related to any auto update of Azure Function App version?
Anonymous

2025-04-01T13:01:54.7233333+00:00
@DJ ,You’re getting 701 errors, and your device couldn’t connect to the APIs around 4 AM UK time. To figure out what’s going on, could you answer a few questions?

Are these APIs hosted in Azure Functions?

If yes, what pricing plan are they on (like Consumption or Premium)?

Have you seen any high memory usage in the Azure portal?

Do the functions connect to other services (e.g., a database)? If so, are those running slow or showing issues?

With these details, we can narrow down the problem. You could also check the Azure Status page, or your Function App logs for clues.
DJ 70 Reputation points

2025-04-01T15:38:26.9766667+00:00

@Anonymous

Thanks for your reply

Yes , the API is an Azure Function App.

I am on consumption plan, does a Premium plan avoid such outages?

It seem the issue i am experiencing is some security issue with HTTPS, my device was able to connect till yesterday using HTTPS but has been stopped and getting some error.

Can you please check if there is any issue with Function All in West Europe related to HTTPS?
Anonymous

2025-04-02T10:59:14.4166667+00:00

@DJ ,

Thank you for the details. I’ve checked and did not find any reported outages in the West Europe region.

Could you please confirm if the issue is still ongoing? If yes, could you share the following details which requested in Private Message.

Looking forward to your response .
DJ 70 Reputation points

2025-04-02T11:13:18.25+00:00

Yes, there is an unplanned maintenance issue do you know anything about it?
Alexandre WAMBRE 10 Reputation points

2025-04-07T10:03:12.36+00:00

Hi DJ, Did you solve this issue?
DJ 70 Reputation points

2025-04-07T10:12:45.8833333+00:00

@Alexandre WAMBRE
Only the unit in our office and the other devices in the field depend on the API for communication. Therefore, until Azue makes the correction, we are simply locked out.

Any idea what can be done on the Azure Side to correct this?

This is caused by some unplanned maintenance we were not aware of.
Alexandre WAMBRE 10 Reputation points

2025-04-07T12:09:19.9266667+00:00

I don't know what's cause the issue. There was also a maintenance but it was concerning backups
DJ 70 Reputation points

2025-04-07T12:16:10.29+00:00

@Alexandre WAMBRE
What was the issue related to backups?
We are using Function Apps, so there are no backup options available. If there is an issue, we need to republish, which we have already done. Our concern is that this API is a core component for our IoT device, and therefore, we cannot be instructed to update the API without due consideration.
Alexandre WAMBRE 10 Reputation points

2025-04-07T12:48:28.4133333+00:00

I don't know what's cause the issue. There was also a maintenance but it was concerning backups
DJ 70 Reputation points

2025-04-07T15:04:27.09+00:00

@Alexandre WAMBRE
Has your device been recovered, as I am still waiting?
Alexandre WAMBRE 10 Reputation points

2025-04-08T09:43:25.7666667+00:00

Yes, we are still waiting on our side as well. But I hope Azure is working on the problem.
DJ 70 Reputation points

2025-04-08T19:22:19.2566667+00:00

@Alexandre WAMBRE are you using any other support channel with Auzure? I am using there professional support to see this can be speeded up, I believe you are based in France?
LeelaRajeshSayana-MSFT 17,866 Reputation points Moderator

2025-04-09T05:18:48.5766667+00:00

@DJ We have escalated this issue to the Product team internally and they are looking into the issue. I will share more details on this as soon as I have an update.
DJ 70 Reputation points

2025-04-09T07:06:54.16+00:00

@LeelaRajeshSayana-MSFT Great, based on our logs with our modem module manufacturer it seems something has changed in the handshake process. Generally how long do they take before a resolution is provided?
DJ 70 Reputation points

2025-04-09T10:47:42.6133333+00:00

@LeelaRajeshSayana-MSFT
Can you please PM?
DJ 70 Reputation points

2025-04-10T14:20:21.59+00:00

@LeelaRajeshSayana-MSFT Any update from product team in regards to the issue?
LeelaRajeshSayana-MSFT 17,866 Reputation points Moderator

2025-04-17T22:30:18.1933333+00:00

@DJ Please let us know if you still seek any assistance with this issue. I understand that this situation may have caused inconvenience, and I want to express my gratitude for your efforts and patience in handling it.

1 answer

Your answer

DJ 70 Reputation points

2025-04-01T11:16:34.64+00:00

Can it be related to any auto update of Azure Function App version?
Anonymous

2025-04-01T13:01:54.7233333+00:00

@DJ ,You’re getting 701 errors, and your device couldn’t connect to the APIs around 4 AM UK time. To figure out what’s going on, could you answer a few questions?

Are these APIs hosted in Azure Functions?

If yes, what pricing plan are they on (like Consumption or Premium)?

Have you seen any high memory usage in the Azure portal?

Do the functions connect to other services (e.g., a database)? If so, are those running slow or showing issues?

With these details, we can narrow down the problem. You could also check the Azure Status page, or your Function App logs for clues.
DJ 70 Reputation points

2025-04-01T15:38:26.9766667+00:00

@Anonymous

Thanks for your reply

Yes , the API is an Azure Function App.

I am on consumption plan, does a Premium plan avoid such outages?

It seem the issue i am experiencing is some security issue with HTTPS, my device was able to connect till yesterday using HTTPS but has been stopped and getting some error.

Can you please check if there is any issue with Function All in West Europe related to HTTPS?
Anonymous

2025-04-02T10:59:14.4166667+00:00

@DJ ,

Thank you for the details. I’ve checked and did not find any reported outages in the West Europe region.

Could you please confirm if the issue is still ongoing? If yes, could you share the following details which requested in Private Message.

Looking forward to your response .
DJ 70 Reputation points

2025-04-02T11:13:18.25+00:00

Yes, there is an unplanned maintenance issue do you know anything about it?
Alexandre WAMBRE 10 Reputation points

2025-04-07T10:03:12.36+00:00

Hi DJ, Did you solve this issue?
DJ 70 Reputation points

2025-04-07T10:12:45.8833333+00:00

@Alexandre WAMBRE
Only the unit in our office and the other devices in the field depend on the API for communication. Therefore, until Azue makes the correction, we are simply locked out.

Any idea what can be done on the Azure Side to correct this?

This is caused by some unplanned maintenance we were not aware of.
Alexandre WAMBRE 10 Reputation points

2025-04-07T12:09:19.9266667+00:00

I don't know what's cause the issue. There was also a maintenance but it was concerning backups
DJ 70 Reputation points

2025-04-07T12:16:10.29+00:00

@Alexandre WAMBRE
What was the issue related to backups?
We are using Function Apps, so there are no backup options available. If there is an issue, we need to republish, which we have already done. Our concern is that this API is a core component for our IoT device, and therefore, we cannot be instructed to update the API without due consideration.
Alexandre WAMBRE 10 Reputation points

2025-04-07T12:48:28.4133333+00:00

I don't know what's cause the issue. There was also a maintenance but it was concerning backups
DJ 70 Reputation points

2025-04-07T15:04:27.09+00:00

@Alexandre WAMBRE
Has your device been recovered, as I am still waiting?
Alexandre WAMBRE 10 Reputation points

2025-04-08T09:43:25.7666667+00:00

Yes, we are still waiting on our side as well. But I hope Azure is working on the problem.
DJ 70 Reputation points

2025-04-08T19:22:19.2566667+00:00

@Alexandre WAMBRE are you using any other support channel with Auzure? I am using there professional support to see this can be speeded up, I believe you are based in France?
LeelaRajeshSayana-MSFT 17,866 Reputation points Moderator

2025-04-09T05:18:48.5766667+00:00

@DJ We have escalated this issue to the Product team internally and they are looking into the issue. I will share more details on this as soon as I have an update.
DJ 70 Reputation points

2025-04-09T07:06:54.16+00:00

@LeelaRajeshSayana-MSFT Great, based on our logs with our modem module manufacturer it seems something has changed in the handshake process. Generally how long do they take before a resolution is provided?
DJ 70 Reputation points

2025-04-09T10:47:42.6133333+00:00

@LeelaRajeshSayana-MSFT
Can you please PM?
DJ 70 Reputation points

2025-04-10T14:20:21.59+00:00

@LeelaRajeshSayana-MSFT Any update from product team in regards to the issue?
LeelaRajeshSayana-MSFT 17,866 Reputation points Moderator

2025-04-17T22:30:18.1933333+00:00

@DJ Please let us know if you still seek any assistance with this issue. I understand that this situation may have caused inconvenience, and I want to express my gratitude for your efforts and patience in handling it.

Answer 1

@DJ Sharing the findings from the product team for the broader group here.

The Microsoft Azure Team has investigated your issue where TLS handshakes to your app were failing.

Upon investigation, engineers determined this to be caused by a regression in TLS handshake logic.

There was a recent change made to our TLS handshake logic to reject requests which do not meet the MinTlsVersion requirement earlier. We did this to improve telemetry on our end and save some CPU cycles for extra processing of the handshake. However, in doing this we inadvertently exposed a bug in the framework we use to parse TLS handshakes related to SSLv3.0 Unified Client Hello.

We reverted the change in question and added extra regression testing to ensure we do not regress again. We also have an Issue opened against the .NET team: Parse more of the ClientHello when using SSL3 in the record layer · Issue #2821 · dotnet/yarp

In order to protect your app in the future, we recommend checking out this guide for ideas about how to be as resilient as possible.

We apologize for any inconvenience.

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Can not access API via device

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