Just got new iPhone X set up last night
Everything working called on phone all day but now when I dial it rings once and hangs up but all other functions work
Press and quickly release the Volume Up button. Press and quickly release the Volume Down button. Then, press and hold the Side button until you see the Apple logo.
Try toggling LTE off and on again.
If you can't make or receive calls on your iPhone - Apple Support
Just got new iPhone X set up last night