How to troubleshoot a Galaxy phone that won't connect to a Wi-Fi network

Check if the router is working properly. Make sure that it's powered on, connected to the Internet, and that your phone is within the router's Wi-Fi range. In addition, if too many devices are connected to one router, the Wi-Fi may not be detected.

Try restarting your Galaxy phone, router, and modem.

Step 1. To restart your phone, tap the Power icon in the Quick panel, then tap Restart.

Step 2. Turn your router and modem off and on again. When turning the router and modem off, unplug the power plug and plug it back in, and then turn on the power. 

Step 3. After you restart each device, see if you fixed the issue.

Follow the steps below to reset the network settings and turn on Wi-Fi again.

Step 1. Go to Settings, and then select General management.

Step 2. Find and select Reset.

Try the Wi-Fi connection in Safe mode. If the Wi-Fi network is connected in Safe Mode, it may be a problem caused by the downloaded app on your phone, and that app should be uninstalled. To find which app causes a Wi-Fi issue, you can try uninstalling the apps in the order of the last installation.

If there is a lock mark inside the Wi-Fi network icon, it is a password protected network. When entering the password, be careful and enter it correctly. Wi-Fi passwords are case-sensitive.

If the above methods do not work, you may bring your device back to the factory default settings just like when you powered on your device for the first time.

Step 1. Go to Settings, and then select General management.

Step 2. Select Reset, and then tap on Factory data reset.

Step 3. Scroll down the page and tap on the Reset button.

Step 4. Tap on the Delete all button.