TAS-106 on /telephony/sessions/{conferenceId}/parties/bring-in during merge; conference create works

Hi everyone,

I’m implementing merge in a Laravel app and need confirmation on expected behavior.

Stack

• PHP SDK: ringcentral/ringcentral-php 3.0.4
• WebPhone SDK (ringcentral-web-phone-2)
• Using call-control + telephony conference APIs

Flow

1. Create conference
   POST /restapi/v1.0/account/~/telephony/conference → 200
2. Bring in active calls into conference
   POST /restapi/v1.0/account/~/telephony/sessions/{conferenceSessionId}/parties/bring-in → 403 TAS-106

Observed app result

• /api/r/call-control/merge returns 409 Conflict
• Message: Bring-in was rejected (TAS-106). Automatic transfer fallback to conference target is disabled.

Sample payload that still fails (even with -1 parties)

• primary_party_id: ...-1
• secondary_party_id: ...-1
• Still gets TAS-106: Operation is not allowed

Scopes
CallControl, ReadPresence, VoipCalling, and other standard scopes are present.

Question
Has anyone seen TAS-106 for bring-in/merge while conference creation works?
Is this usually account/role/call-leg restriction, and what exact setting/feature enables this?