Microsoft MS-721 Exam - Topic 2 Question 47 Discussion

Actual exam question for Microsoft's MS-721 exam

Question #: 47
Topic #: 2

You have a Microsoft Teams Phone deployment.

You are deploying Direct Routing.

All users have a SIP URI in the format of user@contoso.com. The Session Border Controller (SBC) is named sbc.voice.contoso.com.

When troubleshooting errors on the SBC, you receive the warning shown in the following exhibit.

What is a possible cause of the issue?

AThe certificate does not match the FQDN on the SBC.

BThe firewall blocks inbound traffic on port 443 to the SBC.

COnly TLS 1.0 is enabled on the SBC.

DMicrosoft 365 Phone System licenses are not assigned to the users.

Show Suggested Answer

Suggested Answer: B

https://docs.microsoft.com/en-us/microsoftteams/troubleshoot/phone-system/direct-routing/sip-options-tls-certificate-issues

by Carlee at Aug 15, 2025, 12:48 AM

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Celestine

2 months ago

I agree, licenses should be assigned first before troubleshooting.

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Katy

3 months ago

Wait, are licenses really that crucial for this to work?

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Carmela

3 months ago

Sounds like a certificate issue to me.

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Leonard

3 months ago

Definitely check the TLS settings, could be outdated.

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Flo

3 months ago

I think it might be the firewall blocking traffic.

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Tasia

3 months ago

I feel like licensing could be a factor, but I thought that was more about user access than SBC errors. Option D might not be the right choice.

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Dahlia

4 months ago

I’m a bit confused about TLS versions; I know TLS 1.0 is outdated, but I’m not sure if that’s the main issue here.

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Werner

4 months ago

I think I saw a similar question where firewall settings were the issue, so option B could be a possibility too.

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Talia

4 months ago

I remember something about certificates needing to match the FQDN, so option A seems likely, but I'm not completely sure.

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Janine

4 months ago

Ah, I see. If the users don't have the right licenses, that could definitely cause issues with the Direct Routing setup. I'll make sure to verify that.

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Virgina

4 months ago

I think the key here is to methodically go through each option and eliminate the ones that don't seem to fit the problem description. That should help me narrow it down.

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Alecia

5 months ago

Wait, I'm a bit confused. Could it also be an issue with the firewall or TLS settings on the SBC? I'll need to double-check those as well.

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Milly

5 months ago

Okay, let's see here. The warning is about the certificate not matching the FQDN, so that's the first thing I'd check.

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Wai

5 months ago

Hmm, this looks like a tricky one. I'll need to carefully review the details and think through the possible causes.

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Raylene

5 months ago

I agree with Ashton, that seems like a likely reason for the issue.

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Ashton

5 months ago

I think the possible cause could be the firewall blocking outbound traffic on port 443 to Microsoft Teams.

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Harley

6 months ago

TLS 1.2 being enabled on the SBC? That's a wild guess, but hey, maybe the IT team is really into cyber security.

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Maurine

6 months ago

The firewall blocking traffic to the signaling port on the SBC seems like the most likely culprit here. I bet the network admin forgot to open that port.

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