Hi Veronika! Try force re-starting your phone, which can sometimes clear up such problems. On your iPhone Xs:
On the left side of your iPhone press and quickly release the Volume Up button, then press and quickly release the Volume Down button.
Then, on the right side of your iPhone, press and keep holding the side power button (keep holding past the "Slide to shut down"!!) until the Apple Logo appears, then release the power button and let your phone re-boot.
Hope this helps you! Regards, Ian.