When two smartphones are in the same room, but only one successfully connects to the home network, it naturally causes confusion and irritation. The user immediately suspects a faulty router or a malfunctioning device, although more often than not, the cause is incompatible settings or a software glitch.
Digital devices communicate using strict protocols, and the slightest discrepancy in security parameters or frequency characteristics can result in the router simply not allowing a particular device into its ecosystem.
First, you need to run a basic diagnosis: if the internet is available on your tablet or laptop, then the problem is localized in the settings of the affected phone or its interaction with the access point.
In this article, we'll take a detailed look at the technical aspects of wireless modules, which are often overlooked during initial setup.
Hardware limitations and frequency ranges
Modern routers often operate in two bands: 2.4 GHz and 5 GHz. Older smartphone models may not physically support the faster 5 GHz standard, seeing only one of the two available networks or not seeing them at all if the SSIDs are hidden or combined.
If your router is configured to operate in wireless mode only 5 GHz, budget or older devices simply won't detect the access point in the list of available connections. This isn't a malfunction, but a hardware compatibility issue.
It's also worth considering the physical placement of the antennas. Some smartphones have antenna modules positioned in such a way that carrying them in a certain pocket or using a thick case blocks the signal, while other devices with external antennas operate more stable.
⚠️ Note: Some cheap Chinese smartphones have a limited Wi-Fi module that doesn't support channels 12 through 14 in the 2.4 GHz band. If the router is configured for one of these channels, the phone won't see the network.
To check frequency support, you can use special applications or look at the technical specifications of the model on the manufacturer's website.
It often helps to separate network names in the router settings so that you can force the device to connect to the desired range.
IP address conflicts and DHCP settings
One of the most common reasons why one device works while another doesn't is a static IP address conflict. If you manually assigned an address to one device, and the other device tries to obtain the same address automatically, a connection error will occur.
Protocol DHCP The router is responsible for automatically assigning unique numbers to each client. A failure in this mapping table can cause the router to ignore requests from a new device.
The solution often lies in resetting the network settings on the affected phone. This will delete all saved passwords and reset the IP configuration to factory defaults, allowing the router to assign a new address.
☑️ Actions in case of IP conflict
In rare cases, manual DNS server configuration may be required if your ISP blocks default addresses. Try entering Google's DNS settings (8.8.8.8) or Cloudflare.
Make sure that the device is not in Airplane mode, which may block the module from working even after it is turned off.
Encryption and security issues
Wireless network security is ensured by encryption protocols such as WPA2 or the newer WPA3. If your router is configured to use the latest standard, WPA3, then older smartphones may simply not understand this protocol and refuse to connect.
Router settings often include mixed encryption mode (WPA2/WPA3 Mixed), but some devices don't work correctly with this mode enabled. In this case, the router detects the device but terminates the connection during the authentication process.
Check the security type in your router's interface. For maximum compatibility with older devices, we recommend using WPA2-PSK (AES).
It's also worth paying attention to the password length. Some older operating systems have character limits for the security key.
The password must contain only Latin characters, as Cyrillic may be encoded differently on different devices, which will lead to an authorization error.
Memory overflow and software crashes
A smartphone's internal memory isn't just a photo storage area; it also stores system files and network service caches. If the device's memory is critically full (less than 100 MB remaining), the operating system may block background processes responsible for connection maintenance.
Clearing the network service cache often resolves a frozen Wi-Fi module. This can be done through the app settings menu by finding the "Wi-Fi" or "Network Connections" system process.
Outdated phone firmware may also contain bugs that prevent it from working properly with new routers. Check for operating system updates.
⚠️ Important: Before resetting network settings, make sure you remember your Wi-Fi password, as it will be deleted from your phone's memory.
Sometimes the culprit is an installed antivirus or VPN application that intercepts network traffic and blocks the connection. Try disabling them while troubleshooting.
Restarting your device using the "power off and back on" method helps clear temporary driver errors.
Comparison table of causes and solutions
To make diagnosis easier, we've compiled the main symptoms and treatment methods into a single table. This will help you quickly navigate the situation.
| Symptom | Probable cause | Solution method |
|---|---|---|
| The network is not displayed in the list. | Band incompatibility (5 GHz) | Enable 2.4 GHz on your router |
| Error "Failed to connect" | Incorrect password or encryption type | Check the password and change it to WPA2. |
| Connected, but no internet | IP or DNS conflict | Reset network settings, register DNS |
| Weak signal on one device | Antenna hardware problem | Remove the cover and check the integrity of the case. |
| Constant disconnections | Module overheating or interference | Cool down the device, change the Wi-Fi channel |
Use this table as a checklist when troubleshooting. Work your way from simple solutions to complex ones.
If none of the steps help, the problem may lie deeper in the hardware.
The influence of interference and third-party devices
The 2.4 GHz band is heavily congested. Microwaves, Bluetooth headsets, wireless mice, and even neighbors' routers create a jumble of radio waves. One device might have a more powerful receiver and cut through the noise, while another might lose packets.
Check that your router isn't located near a mirror, aquarium, or metal objects. Water and metal can block the signal, creating "dead zones."
Use Wi-Fi analyzer apps (such as Wi-Fi Analyzer) to see what channel your network is on and if there are any neighbors there.
If you have many smart devices in your home (lamps, outlets), they also create a load on the airwaves. The router may not be able to handle the number of simultaneous requests from different clients.
In such cases, installing a repeater or switching to a mesh system that evenly distributes the load helps.
When the router itself is to blame
The router itself shouldn't be discounted either. Routers tend to overheat, especially in the summer or when running 24/7 without powering down. Overheating of the processor leads to malfunctions of the radio module.
The router also has a limit on the number of clients that can connect. If you have a limit (for example, in guest mode), a new phone simply won't be allowed onto the network.
Check your router logs (see the "System Log" section). They may contain entries indicating that the device was denied access due to filtering or a NAT table overflow.
If your router is more than 5-7 years old, its hardware may simply not be able to handle modern encryption standards and the speeds required by new smartphones.
In this case, the only solution is to replace the equipment with a more modern model that supports the Wi-Fi 6 standard.
Frequently Asked Questions (FAQ)
Why does the phone say "Obtaining IP address" and then reset?
This means the handshake with the router was successful, but the router can't allocate an address. Most likely, the DHCP address pool is full or MAC filtering is enabled. Try rebooting the router.
Can a case block Wi-Fi?
Yes, if the case has a metal back panel or inserts. Metal shields the signal. Remove the case and check the signal strength.
What should I do if my phone sees the network but doesn't connect?
Tap the network and select "Forget network." Then re-enter the password. If that doesn't help, check the date and time on your device; incorrect time can block security certificates.
How do I know if my phone supports 5GHz?
Check the model's specifications online. If support for the 802.11ac or 802.11ax standard is indicated, then 5 GHz is supported. 802.11n (Wi-Fi 4) may be supported, but not always.
Will a factory reset help?
Resetting network settings (not a full phone reset) resolves 90% of software conflicts. A full phone reset should be done last, after backing up your data.