Symptoms
Assume that you try to create a meeting by using a Microsoft Skype for Business 2016 client. When you click the "Find a local number" link, all the numbers are displayed. This includes the toll-free numbers. This issue occurs even if the AllowTollFreeDialIn parameter is set to $false by the administrator in your organization.
Resolution
To resolve this issue, install the January 7, 2020, update (KB4484213) for Microsoft Skype for Business 2016. Then, create a GPO to add the following new DWORD registry key and set the value under the subkey:
HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Lync
DWORD EnableCAAIdInDialinUrl = 1
Alternatively, you can enable this fix by creating a custom policy entry, and then adding it to the client policy, as follows:
$x = New-CsClientPolicyEntry -Name "EnableCAAIdInDialinUrl" -Value "true"
Set-CsClientPolicy -Identity "<ClientPolicyName>" -PolicyEntry @{Add=$x}
