Problems with Wi-Fi authentication are most commonly due to problems with the security information associated with the network, such as when a user attempts to log on to a wireless networks with the wrong password. However, connectivity issues and using the wrong type of wireless security protocol can also prevent devices from properly authenticating themselves on a wireless network connection.
Most secured Wi-Fi networks use some form of password authorization as their primary form of security. Authentication errors are inevitable for anyone attempting to log on to such a network without the correct password. In addition, some networks use the Media Access Control address of connected devices to prevent unauthorized devices from connecting to the networks via a process known as MAC filtering. MAC addresses are hard-coded into a given computer, smartphone or other wireless device, so any device that has a MAC address not previously authorized for use on the network cannot successfully authenticate on that network even with the correct password.
Intermittent connection issues can sometimes cause authentication errors since the authentication information may be lost in transit between the device and the network's router. Moving closer to a wireless access point or stopping and restarting Wi-FI on a device may sometimes solve this issue. There are also a number of different encryption schemes, such as Wireless Equivalent Privacy and Wi-Fi Protected Access, used to encrypt authentication data on networks. Selecting the wrong encryption mode can cause authentication errors to occur.