In scenarios where two similar devices, such as switches, are connected directly to each other, a crossover cable is usually required. A crossover cable swaps the transmit and receive pairs, which allows for proper communication between devices of the same type. However, modern switches often support auto MDI-X, which can automatically adjust and accommodate for the required cable type. Given the engineer's situation, since the auto MDI-X did not resolve the connection issue, it suggests that the feature might be disabled or not functioning. Therefore, using a crossover cable can establish the connection as it manually crosses the necessary pairs.