@Condor09: Please can you provide further details of the issue? Is the Phone app stopping/closing down when you attempt to make calls, and are you getting any error messages? Are you still able to send and receive text messages? Are you on a Pay As You Go contract?
In the meantime, please open the Phone app > Tap the 3 dots in the top right > Settings > Supplementary Services > Call Barring > Voice Call, and make sure that all options here are toggled off, 'All Outgoing Calls'. Now, head to Settings > Connections > Flight Mode, and toggle this off if it is enabled. Similarly, head to Settings > Notifications > Do Not Disturb, and toggle this option off.
If the issue persists, please remove your SIM, give the gold contacts a rub, and put it back to see if this helps. If the issue is only affecting certain contacts, please open the Contacts app, select an affected contact, tap the 3 dots in the top right, and select Unblock Contact, if applicable. I also recommend reaching out to your network provider to see if there are any restrictions on your account, or to the service in your current area.
Does this happen intermittently ?
Does this happen in one place or everywhere ?
Does this happen with all calls or specific contacts ?
As a process of elimination try your sim card in another phone and then see what happens.
Your sim card may need Sim Swapping.
Also have a word with your Network's Customer Services to check your account.
Current Phone > Samsung Z Fold³ 5G.