Bluetooth headset only works as sink

[Raphael Mankin]

I have a bluetooth headset that I use with both Ubuntu 18 and 20. On 18 everything works fine, on two different machines; on 20 I can only use the headset as a sink (no mike). When I try to set it in full headset mode (with mike) using pavucontrol the earphones shut down.

The headset is a TaoTronics TT-BH-85

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: blueman 2.1.2-1
ProcVersionSignature: Ubuntu 5.4.0-42.46-generic 5.4.44
Uname: Linux 5.4.0-42-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27.6
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: XFCE
Date: Wed Aug 12 22:55:39 2020
InstallationDate: Installed on 2020-08-09 (3 days ago)
InstallationMedia: Xubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
SourcePackage: blueman
UpgradeStatus: No upgrade log present (probably fresh install)

[Raphael Mankin (raph-p)]

I suspect that this problem is elsewhere in the sound system. Today I tried using a wired headset and, while the microphone was working (others on the call could hear me) I could not hear anything.