Is this happening everywhere when you initiate a call or in a certain area ?
Is this happening with all calls or to a particular contact ?
Does this happen with both outbound and inbound calls ?
Try Settings > General Management > Reset > Reset Network Connection.
As a process of elimination can you try your sim card in another phone and then see what happens.
And if possible another sim card in your phone.
This will help to rule out your sim card , or mobile phone account or the phone at issue.
If I can be of any further help then please don't hesitate. Take care. 😎
Daily Driver > Samsung Galaxy s²³ Ultra 512Gb in Phantom Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "