Unable to Make Inbound and Outbound calls

If you are experiencing issues with making inbound and outbound calls in Microsoft Teams, where calls drop after a few seconds, there are several potential causes and resolutions you can consider:

1. Poor Connectivity: If calls drop after about four seconds, this may be due to poor connectivity or communication issues between the Session Border Controller (SBC) and the SIP proxy. Ensure that your network configuration allows traffic to and from all IP address ranges used for SIP signaling.
2. ICE Connectivity Checks: If calls drop between 10 and 20 seconds without audio, it could be due to missing media information or failed Interactive Connectivity Establishment (ICE) checks. Ensure that the correct ICE candidates are included in the Session Description Protocol (SDP) message from the SBC.
3. Session Timer Issues: If calls drop after several minutes, it may relate to issues with the session timer or session refresh mechanism. Check the SESSION-EXPIRES header in the SIP INVITE message to ensure it is configured correctly and that a reinvite is sent to refresh the session before it ends.

To troubleshoot, you may want to review your network and SBC configurations, ensuring they are set up correctly to handle SIP signaling and media traffic. If other users are facing similar issues, it could indicate a broader problem with the service or configuration that may need to be addressed at the organizational level.

References:

• Issues that affect inbound Direct Routing calls
• Issues that affect outbound direct routing calls

Hi @Manikandan Anbalagan,

 Welcome to the Microsoft Q&A forum.

Thank you for contacting us. We understand that at the moment you are unable to receive incoming calls or make outgoing calls. Please allow us to provide the following information:

Possible causes:

• After an update, Teams may have lost access to your camera and microphone, preventing calls from being made.
• Your subscription might have been unintentionally disabled.

Steps to resolve the issue:

1. Check on Teams Web First, try making a call using Teams Web to see if the issue persists.
   • If you can make calls on the web, the issue may come from the desktop app.
2. If the issue is with the app, follow these steps:
   • Step 1: Clear Teams cache To clear the cache:
   • Press Windows + R
   • Enter the path: %appdata%\Microsoft\Teams
   • Delete all files and folders in this directory.
   • Restart Teams.
   • Step 2: Sign out and sign back in If these two steps do not work, you can uninstall and reinstall Teams on your device.

1. If the same issue occurs on the web, check Teams permissions:
   • Step 1: Search for Settings in the Windows search bar.
   • Step 2: Click Privacy and Security → Click Camera and Microphone to grant access to Teams.
   

If the above steps still do not resolve the issue: We recommend contacting Microsoft Support to check your system, subscription, and any policies that may have been unintentionally applied to your account.

How to raise a support ticket with Microsoft:

• Step 1: Go to https://admin.microsoft.com
• Step 2: Click Get Help & Support
• Step 3: Enter the subject: Need assistance checking Teams calling capability
• Step 4: Choose your preferred contact method.

After completing these steps, a Microsoft live agent will proactively contact you and assist until the issue is fully resolved.

I hope this information is helpful. Please follow these steps and let me know if it works for you. If not, we can work together to resolve this.   

Thank you for your patience and your understanding. If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.

I look forward to hearing from you.

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