Android Internet Fails on One Network After Setting Custom Private DNS

If the failure began after selecting a custom Private DNS hostname, compare that setting with Automatic on the affected network. Preserve the original value so you can restore it. This is a controlled way to investigate name resolution, not a recommendation to disable security features permanently or reset the entire phone.

Establish the scope

Check whether the same ordinary website fails on Wi-Fi but works on mobile data, or vice versa. Then determine whether multiple apps are affected. One app failing is not enough to identify a DNS problem. Keep the test small and avoid sending passwords through an unfamiliar network while access is uncertain.

Google lists Off, Automatic and a provider-hostname mode in Android's Private DNS settings. It recommends retaining Private DNS where usable and explains that it protects DNS traffic rather than every kind of communication. This guide does not certify the custom provider or promise its availability on every network.

Compare one setting

Find Private DNS through Settings search or the manufacturer's network menu. Note the selected mode and exact hostname privately. If the device is managed for work or school, ask the administrator before changing a required control.
Check whether the custom value came from the provider's official instructions. A web address pasted with a scheme, a spelling mistake or an outdated hostname should be corrected with that provider's current guidance, not guesses from a forum.
If you are permitted to change it, select Automatic and save. Reconnect to the affected network and repeat the same ordinary request. Keep VPN, proxy and other network controls unchanged for this first comparison so the result has a clear boundary.
If access returns, investigate the custom provider/network combination before restoring the hostname. Ask the provider or network administrator whether the configuration is supported. Working Automatic mode narrows the issue; it does not prove malicious blocking or a failed phone antenna.
If the failure is unchanged, stop cycling through public DNS names. Restore your required configuration as appropriate and use the broader connection workflow, including the network's legitimate sign-in process if it is a captive network.

Interpret the evidence

Failure only with the custom hostname suggests that configuration is relevant. Failure in both modes leaves connectivity, authorization or another control unresolved. If a captive network still needs login, successful Wi-Fi association alone does not mean internet access has been granted. Treat the administrator's access requirements separately from the DNS setting.

Manufacturer differences

Private DNS paths and permitted controls vary by Android version, Samsung/Pixel software and management policy. Absence of the same menu path is not proof that your phone is defective. Use Settings search and the official manufacturer guidance instead of installing a configuration app with broad network permissions.

Limits and warnings

Do not install an unknown certificate, disable a mandatory work VPN or ignore browser security warnings to complete the experiment. Private DNS is not a complete privacy shield. Return to a trusted connection for account recovery or private support details, and seek administrative help when a managed setting is involved.