We need to get to the root cause.

Meaning

We need to identify the fundamental reason for the problem.

Examples

• John: 'The system keeps crashing.'
• Alice: '<b>We need to get to the root cause.</b> Is it a software bug or a hardware issue?'
• John: '<b>We need to get to the root cause.</b> Is it due to competition, pricing, or something else?'
• Alice: 'Sales are declining.'