The iPhone 8 Plus is a 2017 phone with a 5.5 inch screen, a dual-lens camera and a Wi-Fi radio that supports 802.11ac, and its Wi-Fi faults at this age are usually a saved network that has gone stale, a router that has changed its settings or a phone that needs a software or network reset. Work from the simplest. Turn Wi-Fi off and on in Control Center, and put the phone in Airplane mode for ten seconds.
The checks in more detail
Open Settings, Wi-Fi and tap the i beside your network: if it says Weak Security or shows a warning, the router may be using an older security type that needs changing. Choose Forget This Network, restart the phone and join again with the password, typed carefully. If the phone connects but pages do not load, check the router with another device, and look at the DNS and the Private Wi-Fi Address setting in the network's details: switching Private Address off for your home network can fix routers that do not like a rotating address.
If only your home network fails, restart the router and give it a few minutes, then check whether it uses a Wi-Fi 6-only mode, a hidden name or a very wide channel width, and set it to mixed mode with 80 megahertz on the 5 GHz band for a test. An iPhone 8 Plus does not support Wi-Fi 6, so a router in an exclusive mode will not see it. If every network fails, update iOS to the last version the phone supports, 16, and then reset network settings in Settings, General,
Transfer or Reset iPhone, Reset, Reset Network Settings, which erases saved networks and Bluetooth pairings and often cures a stubborn fault. A grayed-out Wi-Fi switch after a drop or a repair may point to a hardware fault, because the iPhone 8 series had Wi-Fi and Bluetooth module problems after a fall or a failed repair, and a repair shop can check the board. Test the phone on a public network to see whether the fault is the phone or the router. Back up before a reset, since the reset is gentle but a restore is not.
Differential
Likely causes of “Apple iPhone 8 Plus will not connect to Wi-Fi or keeps disconnecting”, and how to tell them apart
- 1
A stale saved network
What separates it Wi-Fi connects badly at home
How to confirm Forget the network and rejoin
- 2
A router setting the phone cannot use
What separates it The network is invisible or drops
How to confirm Use mixed mode and 80 megahertz on 5 GHz
- 3
The Private Wi-Fi Address
What separates it The router rejects the phone
How to confirm Turn it off for this network
- 4
Corrupt network settings
What separates it Every network fails
How to confirm Reset Network Settings
- 5
A hardware fault after a drop
What separates it The Wi-Fi switch is gray
How to confirm Have a repair shop check the board
Before you touch a setting
Record this first — changing settings destroys the evidence
- Whether only one network fails
- The router model and its mode
- The iOS version
- Whether Wi-Fi is grayed out
Try in this order
0 of 6 completedToggle Wi-Fi and Airplane mode
ReversibleTen seconds.
Forget and rejoin
ReversibleThe network.
Turn off Private Address
ReversibleFor this network.
Change the router mode
ReversibleTo mixed with 80 megahertz.
Reset Network Settings
ReversibleIf every network fails.
Check on another network
ReversibleTo judge phone or router.
Model-specific
What is true of this model and not of its siblings
- Wi-Fi 5
- The router must allow older modes.
- Private Address
- It can upset some routers.
Stop boundary
When this stops being a self-service repair
- !If every network fails after a network reset, have the board checked
- !If only the home router fails, change its mode or contact the provider
- !Back up first
Evidence ledger
Sources behind this answer
Exact questions
Common questions
Does the iPhone 8 Plus support Wi-Fi 6?+
No, it supports Wi-Fi 5.
What is the last iOS for it?+
iOS 16.
What does Reset Network Settings erase?+
Saved Wi-Fi networks and Bluetooth pairings.
Why is Wi-Fi grayed out?+
Often a hardware fault after a drop.