Wi-Fi Drops / Intermittent Connectivity (Ubiquiti / TP-Link)

Section: Network & Connectivity Tags: wifi, wireless, drops, ubiquiti, unifi, tp-link, access-point, powerline, intermittent Source tickets: #18970, #25073 Confidence: High — root causes confirmed on-site

Symptom

Users experience intermittent Wi-Fi drops throughout the day. Speed tests are inconsistent. Specific rooms or floors lose connectivity while others are fine. Rebooting the router temporarily fixes the issue. The problem started after a new access point was installed, or worsened over time.

Root Cause

Most common causes in order:

Powerline adapter unreliability — An access point connected via powerline (HomePlug) adapter has intermittent link drops. The powerline itself is sensitive to electrical noise and other devices on the ring. This is the most common cause of "one room is fine, another isn't" patterns.
Access point needs reboot / firmware update — Individual AP stuck in a bad state; rebooting it (not the router) resolves temporarily
SSID roaming issues — Clients "stick" to a distant AP rather than roaming to a closer one; common when mixing AP brands or using old 2.4GHz clients
ISP line fault — The WAN connection itself is intermittent; the Wi-Fi gets blamed when the underlying issue is the broadband

Diagnosis Steps

Step 1 — Identify the affected zone

Ask: is the drop affecting all devices in the building, or only specific rooms?
If all rooms: likely a router/WAN issue → see Step 4
If specific rooms only: likely an AP issue → see Steps 2–3

Step 2 — Check for powerline adapters

Walk the cabling route of each AP. Any AP connected via a powerline adapter (a plug-in device, not a wall-plate ethernet run) is a high-risk point:

Identify the powerline pair serving the affected AP
Plug a laptop directly into the ethernet port of the powerline receiver — run a speed test
If the speed is poor or the link drops: the powerline is the problem

Fix: Replace the powerline with a proper ethernet cable run, or use MoCA adapters (coax-based, more reliable). If cabling is not possible: add a Unifi AP using a long ethernet patch cable routed temporarily and plan a proper cable installation.

Step 3 — Reboot and reconfigure the affected AP

In UniFi Controller (or via the UniFi app): identify the AP serving the affected area
Force-reboot the AP: click the AP → Restart
If issues persist: Forget the AP in the controller and re-adopt it (re-provisioning clears stuck states)
Check firmware: UniFi → Devices → [AP] → Upgrade if a newer version is available
Check channel utilisation: UniFi → RF Environment — look for channel congestion. Switch to a less-congested channel on 2.4GHz (use 1, 6, or 11 only — no overlap) and 5GHz (any non-DFS channel)

For TP-Link boosters/extenders:

Access the TP-Link admin page: http://tplinkwifi.net or the device IP
Factory reset if reconfiguration is needed: hold the reset button for 10 seconds
Reconfigure as a range extender (not router mode) to avoid double-NAT

Step 4 — Diagnose ISP line vs. internal network

To confirm whether the fault is WAN or internal:

Connect a laptop directly to the router/modem via ethernet
Run a continuous ping test to an external IP: ping -t 8.8.8.8 (Windows) or ping -c 100 8.8.8.8 (Mac)
If pings drop while on ethernet: the fault is the ISP line — contact the ISP with ping results
If pings are clean on ethernet but drop on Wi-Fi: the fault is internal

For ISP-side intermittent faults: request an Openreach engineer visit (if on FTTC/FTTP) or a line quality report from the ISP. Provide them with the ping results and timestamps.

Step 5 — Unnecessary router in chain

Some sites have an ISP router plus a separate router, creating double-NAT. Check:

Is there an ASUS, BT Hub, or similar ISP router in line before the client's own router (Draytek, UniFi)?
If so: put the ISP router into modem-only mode (sometimes called "pass-through" or "DMZ host") and let the client's router handle all routing

This eliminates double-NAT and often resolves mysterious drops caused by conflicting DHCP servers.

Remediation Summary

ScenarioFix --------------- One AP drops, powerline usedReplace powerline with ethernet or MoCA One AP drops, ethernet-connectedReboot AP; update firmware; re-adopt in controller All APs intermittent, WAN ping cleanSSID/roaming config issue — check UniFi BSS Transition settings All APs intermittent, WAN ping dropsISP line fault — contact ISP with evidence Double-NATPut ISP router in bridge/modem mode

Verification

After fix: run a continuous ping from the problem area for 30 minutes (ping -c 200 8.8.8.8). Zero packet loss expected. Test file transfers from the affected room to the server. Confirm no drops over a working day.

Prevention

Never use powerline adapters for permanent AP installations — always run ethernet or MoCA
Reserve static DHCP leases for all APs (they should not be getting IPs from DHCP — assign fixed management IPs)
Enable UniFi automatic firmware upgrades for APs (not the gateway — that's higher risk)
Check RF environment annually in busy office buildings as neighbouring networks grow