Bot Transferring Teams User, Leaves Call Leg Remaining

Dr Dave H 150

We use the Graph Cloud Communications API for our Teams Calling Bot to answer an incoming call to the Bot from a Teams user, and then add another Teams user into the call (as per this example (participant: invite - Microsoft Graph v1.0 | Microsoft Learn). If this user does not accept the call, the Bot then transfers the caller (initial Teams user) to either another Teams user or a PSTN number. This is a non-consultative transfer, as given in this example; call: transfer - Microsoft Graph v1.0 | Microsoft Learn

The transfer appears to work fine, however, the initial Teams user incorrectly remains in a call with Bot, even after the transferred call has terminated. Although this fact is not apparent from the Teams client (there is no call window present), if a subsequent call is made from the caller to the same Teams Bot, the Teams client reconnects to the initial call, showing that the call is on hold. Furthermore, if the subsequent Bot call is not made, the Teams user's presence shows they are still in a call, and this presence doesn't change until the call to the Bot is cleared by some means.

We believe that this is a bug within the Teams Client or the Teams core, relating to the Transfer operation.

Steps to Reproduce;

1. Make call into Teams Calling Bot (from Teams user 1)

2. Bot Answers call [Using call: answer]

3. Bot adds Teams user 2 to the call [Using participant: invite]

4. [Teams user 2 doesn't answer the call] Call is left to time-out

5. Bot transfers Teams user 1 to a PSTN number [Using call: transfer]

6. [At this point the Bot sees a message indicating Transfer success but it doesn't suggest that the call is terminated - see below]

7. Drop call between Teams user 1 and the PSTN

8. [Teams user 1 presence indicates they are still in a call]

9. Make call into Teams Calling Bot (from Teams user 1)

10. [Call "reconnects" to original call]

11. Drop this call

12. [At this point the Bot sees a message indicating the call has terminated]

13. [Teams user 1 presence indicates they are no longer in a call]

This is the message received by the Bot at step 6;

Transfer

We would expect this message to have a changeType of "deleted" and a state of "terminated", and for the call to have been terminated. But clearly in this case the transfer operation is not completing correctly.

Any help in this matter will be gratefully received. Cheers, Dave

JimmyYang-MSFT 53,761 Reputation points Microsoft Vendor

2024-04-22T06:04:56.32+00:00

Hi @Dr Dave H

Teams tag is mainly focused on the general issue of Microsoft Teams troubleshooting. According to your description, your question is related to Teams development, which is not in our support scope. So I will remove teams tag from your thread. Thanks for your understanding and patience!
Vaibhav-MSFT 15 Reputation points Microsoft Vendor

2024-04-24T10:58:55.8766667+00:00

Hello Dr Dave H,
Thanks for reporting your issue. We will test this and update you soon.
Dr Dave H 150 Reputation points

2024-07-02T12:59:09.9666667+00:00

Hi @Vaibhav-MSFT , have you any update on this please?
Dinesh Rajagoni (Tata Consultancy Services Limi) 60 Reputation points Microsoft Vendor

2024-08-02T09:10:57.4766667+00:00
Hi Dr Dave H,
Sorry for the delay in the response. It seems that the issue you're experiencing with the Graph Cloud Communications API for your Teams Calling Bot, where the initial Teams user incorrectly remains in a call with the Bot even after the transferred call has terminated. This problem appears to be related to the Teams Client or the Teams core, specifically with the Transfer operation.

Here are the steps to reproduce the issue and the expected behavior:

Make a call into the Teams Calling Bot from Teams user 1.

The Bot answers the call using call: answer.

The Bot adds Teams user 2 to the call using participant: invite.

If Teams user 2 doesn't answer the call, it is left to time-out.

The Bot transfers Teams user 1 to a PSTN number using call: transfer.

The Bot sees a message indicating Transfer success, but it doesn't suggest that the call is terminated.

Drop the call between Teams user 1 and the PSTN.

Teams user 1's presence indicates they are still in a call.

Make another call into the Teams Calling Bot from Teams user 1.

The call reconnects to the original call.

Drop this call.

The Bot sees a message indicating the call has terminated.

Teams user 1's presence indicates they are no longer in a call.

For more details on the API and related operations, please refer to the following documentation: Working with the cloud communications API in Microsoft Graph
Dr Dave H 150 Reputation points

2024-08-02T09:51:16.1233333+00:00

@Dinesh Rajagoni (Tata Consultancy Services Limi) , thanks for your response. When you say it is a known issue, is that simply because I've raised it in this Q&A thread, or do the Microsoft Dev Team acknowledge it is a known issue? I'm a little confused as your response appears to be just quoting parts from my initial post above.

If Microsoft have acknowledged it as an issue, is there any confirmation that this is going to be fixed, and in what timescale. Thanks in advance, Dave
Sayali-MSFT 2,731 Reputation points Microsoft Vendor

2024-08-16T09:25:05.5833333+00:00

@Dr Dave H -Sorry for delay in response, we are checking this with the engineering team. We will let you know once we have any updates on it. Thanks.
Sayali-MSFT 2,731 Reputation points Microsoft Vendor

2024-08-16T18:29:42.46+00:00

@Dr Dave H -Could you please provide call id/correlation id with timestamp (include time zone) for diagnostics?
Dr Dave H 150 Reputation points

2024-08-23T14:15:03.64+00:00

Hi @Sayali-MSFT , I have just recreated the issue (23/08/2024) - Initial call in at 15:00 (BST, GMT+1).

The CallId as seen by the Bot is; 0e003880-d8dd-4a88-92a2-a5d9a2e89f87

The CallChainId is; b2a05992-f353-491e-9a90-822cb1c384b4

Please let me know if you require any further information. Thanks Dave.
Sayali-MSFT 2,731 Reputation points Microsoft Vendor

2024-08-28T10:27:38.14+00:00

@Dr Dave H- The first call has been escalated to group call even user 2 doesn't answer. In this case, the transfer needs to be consultative, otherwise it's actually creating a new call with the orignal caller on hold, which is by design.

So can you try using consultative transfer (transfer with replacement) so that user 1 will be removed from the first call.
Dr Dave H 150 Reputation points

2024-09-03T09:37:45.2133333+00:00

Hi @Sayali-MSFT , many thanks for your response.

it's actually creating a new call with the orignal caller on hold, which is by design.

We understand that, as that's how transfers work in SIP, for example. But once the new call has been answered, surely the old call should be terminated, and not left on hold. The point of a transfer operation is to transfer that particular call leg; it shouldn't remain, assuming that the new call out has been successfully answered.

Another factor which makes us believe this is not the correct functionality, is that the Teams client does not show any evidence of the original call; there is no separate call window showing the call on-hold, which you would expect if the behaviour is by design.

We have tried the same test but changing the transfer operation to include a ReplacesCallId of the original call but this just errors with "replacesCallId matches callId. Cannot replace a call with itself.". We were unsure if that was what you were suggesting or if you were meaning to make a new 1-2-1 call out and then perform a consultative transfer (on answer), replacing the original call. This does work ok but seems an unnecessary work around.

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