Seorang teknisi jaringan sedang mendiagnosis masalah konektivitas pada router industri. Ia menemukan kode kesalahan 'Error Code: 404 - Gateway Timeout'. Berdasarkan manual troubleshooting berikut, tindakan apa yang paling tepat untuk dilakukan pertama kali? Kutipan manual: 'ERROR CODE 404: Gateway Timeout. This typically indicates a failure in communication between the router and the upstream network device. 1. Check physical cable connections to the upstream device. 2. Verify IP configuration on the router and upstream device. 3. Restart the upstream network device. 4. If issue persists, contact network administrator.'