Hi Sofi,
Have a
good day. Thank you for posting in the Microsoft Community.
From your
mentioned description, can we re-confirm from below information from your side?
- Which
operating system you are using? Is it Windows 10 or Mac or any other?
- Whether
you are using In-built (internal) or external audio and video device for Teams?
We
understand that you are using Microsoft Teams web app client, if yes, generally
there is no Device settings option available on Teams web app. But, please try
to double verify browser permissions and settings to allow camera and
microphone to work in Teams.
Below are the detailed steps information:

On the
other hand, to get better experience of Teams, we would suggest you please try
to use Teams desktop application with “new meeting experience” option and see
the result. Here is the detailed information article about New
Meeting and Calling Experience in Microsoft Teams
Here is
the download URL link for Teams: https://teams.microsoft.com/uswe-01/downloads
Please
feel free to contact us. for further assistant. We will further provide you information accordingly.
Regards,
Darpan