WiFi connectivity issues that affect some devices but not others typically stem from a combination of device-specific limitations, router configuration problems, and network interference. The inconsistency often occurs because different devices support varying WiFi standards (e.g., 802.11ac vs. 802.11n), frequency bands (2.4GHz vs. 5GHz), or security protocols (WPA2 vs. WPA3). Router settings like channel selection (e.g., channel 13 being unsupported by older devices) or DHCP limitations can also create disparities, while outdated firmware or drivers may cause compatibility gaps. Environmental factors, such as signal obstruction or interference from neighboring networks, further complicate the issue.

Key findings from the sources include:

• Channel compatibility: Devices may fail to connect if the router uses unsupported channels (e.g., channel 13) ^[2].
• Frequency band mismatches: Older devices might only support 2.4GHz, while newer routers default to 5GHz or dual-band setups ^[4].
• Driver/firmware issues: Outdated network adapters or router firmware can cause selective connectivity problems ^[3][4].
• IP conflicts or DHCP exhaustion: Too many connected devices or static IP misconfigurations can block access for specific devices ^[8].

Root Causes and Device-Specific Solutions

Hardware and Configuration Conflicts

The most common hardware-related issues arise from mismatches between a device’s capabilities and the router’s settings. Older devices, for example, may lack support for modern WiFi standards like 802.11ac or security protocols like WPA3, while routers configured for newer standards can exclude legacy hardware. Frequency band selection plays a critical role: 5GHz bands offer faster speeds but have shorter ranges and poorer penetration through walls, leaving 2.4GHz-only devices (e.g., smart home gadgets or older laptops) stranded if the router prioritizes 5GHz. Channel selection within these bands adds another layer of complexity—devices manufactured for regions where channel 13 is restricted (e.g., the U.S.) will fail to connect if the router uses that channel, even if the band itself is supported ^[2].

• Router channel limitations:
• Channels 1, 6, and 11 are universally supported; channel 13 is restricted in the U.S. and may cause failures for non-European devices ^[2].
• Interference from neighboring networks on overlapping channels (e.g., channels 3–9) can degrade performance for specific devices ^[8].
• Frequency band incompatibility:
• 2.4GHz supports longer ranges but is crowded; 5GHz is faster but may not reach distant devices ^[4].
• Dual-band routers may default to 5GHz, excluding 2.4GHz-only devices unless manually configured ^[9].
• Security protocol mismatches:
• Devices using outdated security (e.g., WEP) won’t connect to WPA2/WPA3 networks ^[4].
• Mixed-mode security (e.g., WPA2/WPA3 transition) can cause authentication failures on older devices ^[3].

A systematic approach to diagnosing these issues involves:

1. Checking the router’s admin panel for channel and band settings, ensuring compatibility with all devices.
2. Testing devices on both 2.4GHz and 5GHz bands to identify band-specific failures.
3. Verifying security protocols and temporarily downgrading (e.g., to WPA2) if legacy devices are affected.

Software and Network Management Issues

Software-related problems often manifest as intermittent connections, authentication errors, or "connected but no internet" scenarios. Outdated network drivers, corrupted WiFi profiles, or misconfigured IP settings can isolate specific devices while others function normally. For example, a Windows laptop might fail to detect networks due to a corrupted driver, while Android phones on the same network work flawlessly ^[7]. Similarly, DHCP (Dynamic Host Configuration Protocol) issues—such as exhausted IP address pools or conflicts—can prevent new devices from obtaining a valid IP, even if existing devices retain connectivity ^[8].

• Driver and firmware updates:
• Outdated WiFi adapters may lack support for modern routers; updating drivers can resolve detection or stability issues ^[3][4].
• Router firmware updates often patch compatibility bugs with specific device models ^[2].
• IP address conflicts:
• DHCP exhaustion occurs when too many devices are connected, leaving no IPs for new ones ^[8].
• Static IP misconfigurations (e.g., duplicate IPs) can block individual devices ^[4].
• Network profile corruption:
• "Forgetting" and reconnecting to the network clears cached credentials that may cause authentication failures ^[3][9].
• Windows’ "Network Reset" tool reinitializes all adapters and settings, resolving persistent issues ^[7].

Troubleshooting steps for software-related problems:

1. Update drivers/firmware: Manually check for updates via Device Manager (Windows) or the router’s admin interface.
2. Reset network settings: Use built-in tools like Windows’ Network Reset or Android’s "Forget Network" option ^[5][7].
3. Monitor DHCP leases: Access the router’s connected devices list to identify IP conflicts or exhaustion ^[8].
4. Test with static IPs: Temporarily assign a static IP to problematic devices to bypass DHCP issues.