Call not sent

[Mohanad627]

I can not make calls when I try to make call on s20 note ultra  the mobile appear to me that (call not sent ) 

Also when I try to open mobile data I get ( scurity policy prevents use of mobile data ) 

I asked they said to me this Knox guard lock !!

[Samsung_specialist]

Hello,

Please follow the steps below:

Step 1. Go to Settings > Software update.​
Step 2. Tap on Download and install.
Step 3. Follow the on-screen instructions.
​Step4. Check your mobile coverage and service status
​Step5: Check your device settings (Settings >> General Management >> reset >> reset all settings).
​Step6. Verify and inspect the SIM card.
​Step7. Contact your network provider.