Hi @Jo Rooney ,
Can you use it for normal calling or other communication apps?
And what do you mean of "not work"? Can't link with your mobile device or can not hear/speak?
I think you could check the meeting or calling settings and status, make sure you are not blocking speaking or muted. Also you could try using the Teams for browsers to check if it's a client side question.
If so, you can try to delete the saved cache and re-sign in. Or you can uninstall Teams and reinstall it.
Best regards,
Lou
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