There are two main reasons why the recipient might see a different number when you call them using 2ndLine:

1. Masking by recipient's country or service provider:

  • Some countries and telephony service providers have the ability to mask caller ID in certain situations. 
  • This is especially common for calls originating from international destinations or virtual numbers like the one provided by 2ndLine.

2. Masking when using virtual numbers:

  • When you use 2ndLine, your caller ID is associated with a virtual number, not your actual phone number.
  • Some recipients' service providers might automatically mask or replace virtual numbers with "random or generic numbers" due to security concerns or other policies.

Additional Points to Consider:

  • Masking can be inconsistent: The displayed number might appear "different each time you call the same person" from the same 2ndLine number.
  • Most countries and operators allow caller ID: This issue is more likely to occur in countries or with providers known for stricter regulations regarding caller ID presentation.

Unfortunately, due to varying regulations and policies, there's no guaranteed way to control how the recipient's phone displays your number when using 2ndLine.

However, if you require consistent caller ID display, it's recommended to:

  • Check with the recipient's country and service provider to see if they have any restrictions on displaying international or virtual numbers.
  • Consider using a traditional phone service provider that offers a dedicated phone number instead of a virtual one.