Applies To

Call2Teams - Customer

Note: Phone App is available as an additional 'add-on' to existing PBX or Trunk services. If the options is not available in the portal then the service has not been provisioned to the account and needs to be enabled via the licensing provider. 

Phone App is currently only avalible to Call2Teams for PBX users. (Call2Teams for Trunks coming soon!) 


This article outlines some of the common issue with setting up Phone App and the suggested resolution.

1) Users not showing in the Add Users list

The most likley cause of this is a user or the tenant not being set to Teams Only mode.

In the Sync Now log the following type of message will be reported:

Excluded 2 users ineligible for Phone App as they are not in TeamsOnly mode for Teams Upgrade.

Review this setup article for remedial instructions on setting a user or the entire account to Teams Only mode: Click here

If your still getting this error message then please see this link regarding TeamsOnly Mode still not working

2) Calls not going through to a Teams user - '603 Call Declined' in call log

This issue is a result of the customer Microsoft 365 account not being correctly set for External Access and allowing the Phone App domain.

The solution is to allow the Phone App domain on the Microsoft 365 tenant in the external access settings, or allow all domains

Directions for setting External Access for Phone App are available in this article Phone App (Overview)

Note: it can take some time (maybe several hours) for the External Access domain settings to take effect in the Teams admin center

3) Unable a take call off hold

Some Teams clients are affected by an issue with taking a Phone App call off hold (after the user has put the call on-hold).

This is a known issue and is being resolved with a software update.

Affected customers should log a ticket to be notified when the issue is resolved.

4) Using Phone App with a Trunk service (call failure)

Currently Phone App is optimised for operation with the PBX service as a softphone extension.  Compatibility with Trunk services is planned but not yet available. Attempting to user Phone App with a Trunk service will cause the call to fail with an error message.

It is planned that the Phone App will work with a Trunk service and this article will be updated accordingly.

Using Network view (F12) to see error message

In rare cases we may require you to run a network view while trying to place a call with Phone App. To do this open the network view tab within your browser (the Teams client should be running in the browser) and press the call button with a number populated. 

Clicking on the word "Dial" should then give you a response Tab to see the error code (example below)