Others can't here me during phone calls

Apps & Core Settings
1

Hi everyone,

I just got a new phone from the iode store. It’s a refurbished Galaxy S10 that came preinstalled with 6.4-20250521-beyond1lte.

Now unfortunately I had to find out that the mic isn’t working during phone calls. That is via the regular shipped phone app, and it’s also during Signal voice calls for example.
A 3.5mm headphone works.

I’m not muted via the button. And both apps have the mic permission.

I feared there might be a physical defect. So I did a cross check with the preinstalled voice recorder - and that is working.

So what can I do?