If your WiFi is visible, but the frame won't connect to it at all, it is usually an indication that something is wrong with either the password or the encryption of the WiFi.
If your WiFi is not visible at all, please check out the article: My WiFi is not showing on the frame
If your frame connects to the WiFi, but states "No internet" or "Unknown" under Connection status, please check out the article: WiFi connected - no or unknown internet connection
If your WiFi uses a captive portal (a sort of webpage where you enter credentials before you are able to log on - common for public WiFis, work WiFis and guest WiFis) please check out the article: How to connect the frame to a Captive Portal
Troubleshooting steps:
Reboot Network Equipment
Sometimes it may be necessary to reboot (turn off and turn on) your network equipment.
Try to reboot your router, modem and access points
Reboot Frame
If your frame is not behaving as intended, it it always a good idea to try to reboot it.
You can turn off the frame with the power button in the quick menu.
Do not unplug the frame while it's still running.
Double check that the password is entered correctly
To ensure that you enter the password correctly, you can press the 
icon next to the password field. This will make the password visible while typing and allows you to double check that the password is entered correctly.
WiFi encryption
All password protected WiFi connections use a certain encryption type, but outdated encryption types may not be supported. We recommended that you use WPA2 encryption for a secure and compatible WiFi.
Enterprise encryption and WPA3 are currently not supported.
We suggest that you contact your Internet Service Provider or someone tech savvy to change this setting if needed.