12 · Troubleshooting
The response code is the branch. A story without codes is not a diagnosis.
Order the messages. INVITE, 100, 180 or 183, 200, ACK, then later BYE. 183 is early media, not an answer. 488 means the SDP was refused. 408 means something did not answer in time. 503 means the hop is refusing service. 487 often means the caller cancelled.
Join on Call-ID. Two calls that start in the same second are not the same call. Read the first non-success on the hop that sent it, then stop. Do not restart a healthy SBC because a 180 felt slow.
Follow one Call-ID. 183 is not an answer. 488 is codecs. 503 is a hop refusing work.
I read the first failing response on one Call-ID.
If it fails: Two captures are compared and they are different calls.
A colleague reports: HQ looks terrible because the VPN pool was labeled HQ. Where do you start?
HQ looks terrible because the VPN pool was labeled HQ. Confirm the subnet-to-building map before you trust a building chart. Source: https://learn.microsoft.com/en-us/microsoftteams/cqd-what-is-call-quality-dashboard accessed 2026-10-14.
Which description of Poor stream clues is accurate?
Teach yourself to look at jitter, packet loss, and round-trip time separately. A mark of DSCP 0 plus high jitter is a different fault from 12% loss with EF still set. One ‘poor’ label hides the cause. Source: https://learn.microsoft.com/en-us/microsoftteams/cqd-what-is-call-quality-dashboard accessed 2026-10-14.
A colleague reports: The ticket says ‘Teams is down’ and loss is 0.2% with a 600 ms RTT. Where do you start?
The ticket says ‘Teams is down’ and loss is 0.2% with a 600 ms RTT. Capture at the egress and compare with CQD. Source: https://learn.microsoft.com/en-us/microsoftteams/cqd-what-is-call-quality-dashboard accessed 2026-10-14.
Around the call: compliance recording, workforce management, emergency location, analytics, CRM screen pop, and an agent with a human escape. Each one has its own failure.
Two captures are compared and they are different calls.
Cisco CUBE is one of the SBC families named in this lab’s certification lesson. A certified release can be the Direct Routing SBC between Unified CM and Teams.
The tenant still needs a verified domain on the SBC FQDN, and the user still needs Teams Phone. The studio translator does not open a live AXL session. Confirm the current certified release before you build.
Teams Phone and Webex Calling are separate clouds. This lab does not describe a feature that registers a Webex Calling user into a Teams tenant.
A number move is usually a carrier port, a certified SBC, or a meetings interop product. Confirm before relying.
Unified CCE stays the ACD until you migrate it. Microsoft’s contact-center articles name Connect, Extend, and Unify. They do not name a UCCE connector in the notes this lab cites.
Voice into Teams is still Direct Routing or Operator Connect. The routing script stays on the contact-center product you bought. Confirm the vendor’s current model. Source: https://learn.microsoft.com/en-us/microsoftteams/teams-contact-center.
Copilot Studio, Azure Communication Services, and Graph are later tracks in this lab. Treat any uncited limit as confirm before relying.
Opened 2026-10. A row marked confirm did not open. Wikipedia is background. The Teams blog row is the community index.
