ntermittent WiFi clients unable to obtain IP / no Layer 2 connectivity – NWA130BE (Nebula)

We are experiencing an issue within our wireless network where client devices intermittently fail to connect to the network.

Environment:

• AP Model: Zyxel NWA130BE
• Switch Model: Zyxel XMG1930-30HP (We do have other HP switches as part of the LAN network)
• Management: Zyxel Nebula Control Center
• Firmware:
  • AP: V7.30(ACIL.3)
  • Switch: V4.80(ACAS.4)

Symptoms:

• Clients connect to SSID but show “Connected, no internet”
• Devices receive 169.254.x.x addresses
• Issue occurs across multiple APs
• Wired connections function normally
• In the nebula portal Its states" xx failed to receive an IP address due to DHCP failure/timeout…"

Troubleshooting performed:

• DHCP scope checked (83% free)
• DHCP services restarted
• Lease time reduced
• Static IP assigned → still no connectivity
• Tested across multiple APs
• Verified RF/channel utilisation (low usage)
• Confirmed no DHCP snooping configured
• Packet capture performed

Packet Capture Findings:

• DHCP Discover and Request observed
• No DHCP Offer received by client
• Repeated ARP requests:
  • “Who has 10.x.x.x”
  • No ARP replies received

Key Finding:

Even with static IP configuration:

• Clients cannot communicate with gateway
• ARP resolution fails

I believe this indicates:

Layer 2 return traffic is not reaching wireless clients

Impact:

• Intermittent loss of connectivity for student/staff devices
• Affects multiple APs and locations

Request:

Please advise if this is:

• A known issue with firmware V7.30(ACIL.3)
• Related to AP bridging/forwarding behaviour in Nebula mode

And recommend:

• Firmware version to downgrade to (if applicable)
• Any known fixes or patches

Many thanks in advance 😀