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FDN means Fixed Dialing Numbers. It is a feature on your phone that restricts calls to just the ones in your contacts list or address book / phone-numbers-list.
You need to disable FDN as a feature.
First, go to Main menu, then to Settings, then to Call Settings, then see if FDN / Fixed Dialing Number is ***** as an option and Enabled or selected. If it shows up there, Disable it or de-select it.
If it is not showing up there, do a soft restart of your phone (*not* a hard reset) and the option should show up immediately after the soft restart.
Did you do a soft reset or soft restart of your phone?
If so, you may have been issued an improper SIM card, with FDN restriction immovably activated on it, and if that's the case, you'll need to get the store that provided it to swap your SIM card. This sort of problem is not normal, so something is wrong with either the phone (I doubt it) or the SIM card (much more likely.)