The current pre-release of the client ("pioneer" in the version) is only compatible to itself. So you can only play with other testers. Please be aware!
Do you not get a popup with the "warning: SND: XACT3DApply failed." issue? Last client should auto-detect such things.
Solution: https://forum.faforever.com/topic/4084/solutions-for-snd-error-xact-invalid-arg-xact3dapply-failed/1?_=1701727567076
