There are two parts to this topic:
1) Completed: Bypass the lobby for PSTN: The ability for admins and organizers to be able to specify a meeting option to bypass the PSTN lobby independently of the VoIP lobby.
2) On the backlog: Ability for an organizer joined via PSTN to admit users from the lobby with a PIN. If you enable “Always let callers bypass the lobby” in your meeting options, people calling in by phone will join your meeting without having to wait for someone to admit them. See details here: https://support.microsoft.com/office/change-participant-settings-for-a-teams-meeting-53261366-dbd5-45f9-aae9-a70e6354f88e
Please Note: In Q2CY20, we launched a new default in for the Teams meeting policy (https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=63388). If tenants have not modified their default meeting policy, lobby is now enforced.
An error occurred while saving the commentJim from NZ commented
I recently had a related (?) problem. I set up a meeting on MS Teams and invited a non-Teams user to the meeting. When I joined the meeting, they were waiting in the lobby. I clicked "Admit" but then they were stuck in the ether - we waited 3 or 4 minutes but they were not admitted. So we gave up and used a mobile phone on speaker. Not very satisfactory.