There are numerous explanations behind the equivalent.
Some of them are:
1. Too numerous clients calling simultaneously.
2. Customers calling at non-operational hours.
3. You are in a significant conference.
Presently what are the choices that you have as an entrepreneur?
1. Have a replying mail or phone message to welcome your clients.
2. Hire more individuals in your office to go to inbound calls.
3. Outsource your necessity to an inbound call place.