Forget the network and re-enter the password carefully (it's case-sensitive), restart the router and phone, and if the router uses WPA3, switch it to WPA2/WPA3 mixed. Reset Wi-Fi settings if it continues.

The short explanation

Authentication is the password and security check when joining Wi-Fi. A changed password, a typo, a router switched to WPA3-only, or a router that’s reached its client limit all produce this message.

What you'll see

  • “Authentication problem” under the Wi-Fi name.
  • Phone keeps trying to connect then gives up.

Common causes

  • Wrong or changed password.
  • Security mode mismatch (WPA3-only).
  • Router glitch or client limit.
  • Stale saved network.

How to fix it

  1. Forget and rejoinLong-press the network → Forget, then enter the password again.
  2. Restart router and phonePower-cycle both.
  3. Check router securityUse WPA2-PSK (AES) or WPA2/WPA3 mixed mode.
  4. Toggle Airplane modeOn for 15 seconds, then off.
  5. Reset network settingsSettings → System → Reset options → Reset Wi-Fi, mobile & Bluetooth.
Check it's fixed: The phone connects and shows 'Connected'.

Stop it happening again

Use mixed security modes if you have older devices.