Even an experienced user can be perplexed when two smartphones are in the same room, connected to the same wireless network, but one device completely ignores the router. At first glance, it seems like the problem lies with the device itself, but statistics show that in most cases, the root cause lies deeper—in the nuances of security protocol settings or IP address conflicts. Often, owners blame the phone's "weak reception," unaware that the router simply can't negotiate connection parameters with a specific client.
The differences in the operation of network modules from different manufacturers are colossal. iPhone may require strict compliance with WPA3 standards, budget AndroidA smartphone may stumble over DFS channels or dynamic channel width changes. Understanding how the handshake between the device and the access point occurs allows you to eliminate half of the problems without rebooting the device. In this article, we'll take a detailed look at the technical aspects behind the "Obtaining IP Address" error or the endless authorization loop.
It's important to note that diagnostics should be performed methodically, starting with software settings and ending with the physical interaction between the radio modules. Don't rush into resetting the network settings to factory defaults, as this will lose saved passwords for other access points. A manually assigned static IP address on a problematic device is the #1 cause of conflicts in 40% of cases. Let's take everything in order so that you can accurately determine the source of the failure.
IP addressing and DHCP server conflicts
The most common reason why one device works reliably while another doesn't is due to network address allocation. DHCP (Dynamic Host Configuration Protocol) automatically assigns each new client a unique IP address from a preset pool. If the problematic phone previously had static settings for another network, it may attempt to connect to the home network with an address that the router has already assigned to another device or that isn't even within the current subnet range.
When two devices attempt to use the same IP address, the router blocks the connection of the second device to avoid data packet collisions. In logs, this often appears as an endless wait or a sudden disconnect immediately after successful authorization. It's important to check whether the IP, DNS, or gateway settings on the phone are set to manual, especially if the device was previously used on a corporate network or at a friend's with a non-standard configuration.
To fix the problem, go to the WiFi settings on your mobile device, select your network (or forget it), and check the IP settings. In modern interfaces Android And iOS This is hidden in the advanced settings. Make sure "Automatic (DHCP)" is selected, not "Manual." If the problem persists, you can try changing the device's MAC address in the WiFi privacy settings, as the router may have "remembered" the old MAC address with an erroneous binding.
There's another nuance related to address leasing. The DHCP server issues addresses for a specific period of time (the lease time). If a phone hasn't connected to the network for a long time and its address has been leased to another device, it may be refused reconnection until the timer expires or the router's ARP table is reset. In such cases, rebooting the router can help, as this clears the cache of active leases.
Incompatibility of encryption and security standards
Modern routers often operate in hybrid security mode, supporting both WPA2 and the newer WPA3. Older or budget smartphones may simply not detect the network if the router is set to "WPA3 Only" or "WPA2/WPA3 Mixed" with certain SAE (Simultaneous Authentication of Equals) settings. While a flagship phone might easily connect to the new protocol within a year or two, a three-year-old device might ignore the access point or return an authentication error.
⚠️ Attention: When switching your router's security mode from WPA2 to WPA3, all devices that don't support the new standard will lose connectivity. Ensure that critical IoT devices (light bulbs, power outlets) are compatible with the new protocols before updating your router's firmware.
It's also worth paying attention to the type of data encryption. TKIP (Temporal Key Integrity Protocol) is considered outdated and insecure, so many new phones by default refuse to connect to networks that use it (usually in WPA/TKIP mode). If your router is configured to use WPA/WPA2 Mixed with encryption TKIP+AES, try to force it to be set only AES (CCMP). This will improve security and compatibility with modern gadgets.
Another hidden cause could be the "Protected Management" feature or MAC address filtering, which could have been accidentally activated or previously configured by the administrator. In this case, the router sees the device but deliberately blocks its access to the network, even if the password is entered correctly. Check the list of blocked clients in the router's web interface at Wireless → MAC Filtering or similar.
Problems with the 2.4 GHz and 5 GHz frequency bands
Dual-band routers broadcast two networks: 2.4 GHz and 5 GHz. They can have the same name (SSID) and password, which enables Band Steering technology. However, not all phones handle this configuration correctly. If one device only supports 2.4 GHz, and the router is currently pushing it onto the congested, narrow-bandwidth 5 GHz channel, the connection may fail.
Furthermore, the 5 GHz standard has less penetration. A phone might "see" the network, but the signal strength will be insufficient to complete the handshake, while another device with a more sensitive Wi-Fi module will connect without issue. There's also an issue with DFS (Dynamic Frequency Selection) channels in the 5 GHz band. If the router selects a channel that requires radar scanning, some phones may simply ignore the network until the scan is complete or may not support DFS channels at all.
To diagnose, try temporarily separating the networks by giving them different names, for example, HomeWiFi And HomeWiFi_5GConnect the problematic phone to each of them separately. This will help you determine which band is causing the problem. If the phone doesn't see the 5 GHz network at all, check its specifications—it may only support 2.4 GHz.
Channel width also plays a role. If your router is set to 80 MHz or 160 MHz for maximum speed, older WiFi modules may struggle to stabilize the connection due to high noise levels. Try forcing the channel width to 20 MHz or 40 MHz in your router settings. This will reduce maximum speed but significantly improve connection stability for older or budget devices.
DHCP pool and maximum client limits
Every router has a software limit on the number of simultaneously connected clients. For home routers, this limit is often 15-32 devices. If you have a smart home with dozens of light bulbs, cameras, TVs, and phones, the address pool may be exhausted. In this situation, a new phone (or one whose IP lease has expired) simply won't receive an address, while devices already connected will continue to function.
You can check this by logging into the router interface and looking at the list of connected clients (Attached Devices). If the number is close to the limit, you should either disable unused devices or expand the DHCP range. The default range often looks like this: 192.168.1.100 — 192.168.1.200, which gives a total of 100 addresses, but if the range is narrowed manually, there may not be enough space.
| Parameter | Standard value | Recommended for smart home | Impact on the problem |
|---|---|---|---|
| Initial IP | 192.168.1.100 | 192.168.1.2 | Expands the pool of available addresses |
| Final IP | 192.168.1.200 | 192.168.1.254 | Increases the number of seats |
| Lease Time | 120 min | 1440 min (24 h) | Reduces DHCP load |
| Max clients | 32 | Depends on the router | Limiting new connections |
Additionally, some routers have a "Guest Network" feature with a separate user limit. If you try to connect your phone to the guest network and the limit is reached, the connection will fail. Make sure you're connecting to the main network (Main SSID), not the guest network, unless that's your intention.
Network cache and software glitches in smartphone OS
Operating systems Android And iOS Store connection profiles in a special cache. Over time, this data can become corrupted, especially after updating your phone's firmware or changing your router's security settings. The phone may "remember" the old password or encryption type and attempt to use it, ignoring the access point's current requirements. As a result, we see a loop: "Connecting..." -> "Error."
The first step in this situation is to "Forget Network." This deletes the saved profile, including passwords and static IP addresses. You'll then need to re-enter the password. If this doesn't help, a more thorough reset of network settings is recommended. Android this is done through Settings → System → Reset settings → Reset network, WiFi, and mobile data settingsOn . iPhone path: Settings → General → Transfer or reset iPhone → Reset → Reset Network Settings.
⚠️ Attention: Resetting network settings will delete all saved WiFi passwords, Bluetooth pairing settings, and VPN profiles. Make sure you remember the passwords for important networks or have them written down before performing this procedure.
It's also worth checking if your phone has "Data Saver" or "Power Saver" mode enabled, which can block background network scanning or aggressive WiFi scanning. In some skins (for example, MIUI or EMUI) There are strict limits on background processes that can interfere with the normal operation of the network stack. Try disabling battery optimization for system WiFi services.
Hardware features and signal interference
The physical layer also plays a role. Antennas are positioned differently in different phones. One smartphone might have the antenna at the top, while another might have it at the bottom. Holding phones a certain way can block the signal ("death grip"). Furthermore, receiver sensitivity (Rx sensitivity) varies. A flagship phone might "pick up" a signal where a budget model might see nothing.
Interference is another enemy. Microwaves, wireless headphones, baby monitors, and even Christmas lights can create strong interference in the 2.4 GHz band. If one phone has a better interference filter, it will connect, but the other won't. Try moving closer to the router or, conversely, moving to another room to eliminate the influence of local noise sources.
In rare cases, the problem lies in the hardware of the phone's WiFi module itself. Overheating, moisture, or a manufacturing defect can all cause signal degradation. If the phone doesn't connect to any network (home or public), while other devices work fine everywhere, the likelihood of a hardware failure is high. In this case, only diagnostics at a service center can help.
Frequently Asked Questions (FAQ)
Why does my phone say "Obtaining IP address" and then reset?
This is a classic sign of an IP address conflict or an overflowing DHCP pool on the router. The issue could also be an incorrectly set time on the phone (a discrepancy of more than 5 minutes can block a secure connection) or an incompatible encryption mode.
Can antivirus software block WiFi connections?
Yes, some mobile antivirus and memory cleaning apps have protection against fake access points (Fake AP). If your router has non-standard settings or layout, the app may detect the network as unsafe and block the connection. Try temporarily disabling this protection.
What should I do if my phone sees the network but won't connect after changing the password?
Be sure to "Forget Network" on your phone. The device will attempt to log in with the old cached password, and the router will reject the connection. After deleting the profile, re-enter the new password.
Does the set date and time affect the connection?
Yes, it's critical. Security protocols (WPA2/WPA3) use certificates and timestamps. If the phone's time is significantly different from the actual time (for example, if the battery is dead), the handshake with the router won't work, and you'll get an authentication error.
Will resetting the router to factory settings help?
This is a radical, but often effective, solution. A reset will clear all configuration errors, the DHCP cache, and any MAC address blocks. However, keep in mind that you'll have to reconfigure your internet (PPPoE, L2TP, etc.) and WiFi settings afterward.