In the 3CX Management Console:
- Go to Settings
- Click Blacklisted Numbers
- Click “Add.”
- There will be two fields to fill out: “Incoming caller ID to be blocked” and “Description.” In the first field, enter the full phone number or caller ID that you want to block.
Note: The information must match precisely, including case: “jeremy” and “Jeremy” are considered to be different. (You can use an asterisk to cover both situations: “*eremy”.) Make sure you pay attention to what information your phone service provider displays, because the information needs to be exact. For example, some providers display the country prefix (in the US, the “1” before a 10-digit phone number), while others don’t. If your provider does, you need to as well. The same precaution applies to blocking by caller ID: it must be exact, or it won’t work.
- The “Description” field is for you to know why you blocked the number.
- After you’ve filled the information in, click “Ok” and you’re good to go!