ISP Wireless - Station Radio Won't Connect to Access Point

This article describes possible causes and solutions for when a station radio won't connect to an access point. These are the possible causes and recommended actions described in this article:

Compatibility Between Radios

Frequency: Radios must use the same frequency range. As an example, M5 and M2 products are not compatible.
Wave: Wave products use the proprietary 60GHz Wave Technology platform, and can only communicate with other Wave products. Other 60GHz products such as GigaBeam, AF60, AF60-XR, etc. cannot connect to the Wave AP. One exception is the AF60-LR, which can be upgraded with a special Wave firmware to connect as a Wave client.

LTU: LTU products use the proprietary LTU Technology platform, and can only communicate with other LTU products. An exception is the AF-5XHD, which can be upgraded to a special LTU firmware for compatibility with other AF-5XHD, but only in PTP links.

airFiber: airFiber products use a proprietary wireless communication platform, and can only communicate with other airFiber products built on the same platform. For example, AF-5 & AF-5XHD are incompatible. An exception is the AF24 & AF24-HD, which use the same platform, but feature different antenna gain (and can therefore connect to each other).

airMAX M: Any airMAX access point (AP) with the airMAX protocol active will not allow connections from stations that are not airMAX-ready. To connect non-airMAX clients, you would have to disable the airMAX protocol on the AP. Note that disabling airMAX is not recommended since airMAX provides the best possible performance in outdoor wireless networks, so do so only if there is no other solution.
airMAX-AC: airMAX M devices are only able to connect to airMAX AC Access Points. But AC devices cannot connect to an M device configured as an access point.

Compatibility Between airMAX AC & airMAX M Device

Our airMAX AC radios running airOS 8 or later may be configured in PTMP-AP mode to receive airMAX M clients. While in PTMP-AP mode, only 10/20/40MHz channel widths are supported. Follow these steps to perform configuration:

  1. Make sure your airMAX AC AP is upgraded to the current stable firmware.
  2. Upgrade all airMAX M clients to the current stable firmware.
  3. On the airMAX AC AP, be sure to selected "Mixed Mode PTMP-AP" for wireless mode.
  4. If using encryption (recommended) don't forget to note the WPA2-AES pre-shared key.
  5. Save changes made on the Wireless tab with the "Save Changes" button at the bottom.

Only airMAX M series radios running airOS 6 or later may be configured in PTMP-Station mode to connect to Mixed PTMP-AP . While in PTMP-AP mode, only 10/20/40MHz channel widths are supported. Follow these steps to configure the Station:

  1. Navigate to the radio's web interface ( on factory default units).
  2. Confirm the radio is on the current firmware release on the Main tab.
  3. Navigate to the Wireless tab.
  4. Set Wireless mode to "Station" and enable WDS (Transparent Bridge Mode).
  5. Confirm channel width matches AP configuration (20MHz in this example or Auto 20/40MHz).
  6. If using Wireless Encryption, set "Security" to WPA2-AES/PSK.
  7. Set the SSID to match the AP or use the "Select" button to find the Mixed Mode Wireless Network.  It should show as airMAX AC under "Radio Mode".
  8. Hit the "Change" button to apply the settings and then "Apply" to commit.

In case you continue to experience problems, check the following troubleshooting step checklist:

  • Compatible SSID and WPA2-AES values on both radios.
  • Compatible channel width.
  • Disable any frequency lists and confirm the Station supports the AP operating frequency.
  • Due to the number of channels available in the 5GHz band, it can sometimes take several minutes for a radio to connect. Especially if the AP is using a DFS frequency that requires a wait time before transmitting.
  • Confirm radios are on firmware that supports mixed mode operation: airOS 8+ for AC devices and airOS 6+ for M devices.

Compatibility Between a Legacy Station and an airMAX M Access Point

  1. Upgrade the Legacy station to version 4.x. Find downloads here.
  2. Upgrade airMAX M AP version 6.x.
  3. Now Legacy radios can connect to airMAX M APs with airMAX enabled.
  4. Navigate to the airMAX M AP's GUI.
  5. Make sure that airSelect is not enabled.

Compatibility Between Non-Ubiquiti Radios and an airMAX M Access Point

  1. Navigate to the airMAX AP's GUI.
  2. Navigate to the airMAX tab.
  3. Disable airMAX protocol on airMAX.
  4. Click "Change" then "Apply."
  5. Now the airMAX M AP will use the 802.11 CSMA / CA protocol to work with other stations.
  6. Navigate to the Wireless page and ensure that "Channel Shifting" is disabled.

Misconfiguration on Access Point or Station 

  1. Navigate to the Wireless pages of both AP and Station.
  2. Check that wireless settings match on AP and Station, including:
    • SSID
    • Wireless Security: As of firmware versions 6.1.9 on M series and 8.5.11 on AC series, default security is WPA2-AES with the password `0000:0000`.
    • Channel widths (e.g., AP = 40MHz & Station = 40 / 20MHz)
    • Operating frequencies
    • Channel shifting
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