Cannot connect to internet...troubleshooting says authentication failed

Was your SSID password changed? verify your wifi settings.

Router ?

Problems authenticating a router in a computer is a common problem when installing a router or if your internet service gets disrupted. It is easy to solve and only requires a few steps to fix. A router forwards data from a computer to a computer network. The network can be between multiple computers, such as one would need in an office. The network can also, and more usually in households, used for connecting to the internet. Open "System Preferences" in the Applications folder in Finder. Open "Network" under "Internet and Wireless." Click "Advanced" and select "TCP/IP." Select "Renew DHCP License" and click ok. Attempt to connect to the internet. If the internet is still not connecting, restart the router and try the steps again. b> For non-Macs b> Open "Wireless Network Connection" from the wireless tab at the bottom of the screen. Select "Change Advanced Settings." Choose the "Wireless Networks" tab. Choose the wireless network you want to connect to and select the "Properties" button. Under the "Association" tab, make sure the Network Authentication has the proper security level chosen. Enter your network key if your security code is anything other than "Open" or "Shared." Select OK and try to connect. Go Back to "Wireless Networks" tab -> "Properties" and click on "Authentication" tab and un-select the "Enable authentication for the network" selection if the network key is still not authenticating the router. Select OK and try to connect.
Hope this helps.

The error msg "packet data authentication failed" is displayed when connecting to internet via cell phone, even after having the original configuration settings provided by the supplier set to default. The problem can be solved by the following method or else contact the service provider. >Delete the old settings and then by switch off the phone. >Remove the sim card and reinsert it, after some time >gett the new settings and set it to default. Hope this helps. I had the same prblem. Even after calling cc, nothing helped. I tried all things but failed. Then unfortunately, i entered the url of the sp in the access point setting manually and wow it worked. I did this by using uninor.

Solution : Make Sure the SMTP (Mail) Server is an Open Relay Server or Uses POP-Before-SMTP Authentication The mail server being used must be an Open Relay server or use POP before SMTP authentication. If the mail server being used requires SMTP authentication, the scan to e-mail process will fail. The WorkCentre is unable to access the mail server when SMTP authentication is required. Contact your Internet Service Provider (ISP) or System Administrator for additional information.
NOTE: The WorkCentre was designed to send e-mail through internal corporate mail servers. In most cases, if using your Internet Service Provider (ISP) mail server, the scan to e-mail process will fail because most ISP mail servers require SMTP authentication to send mail. Contact your ISP for additional information.

Just for you to be aware, a red light on the router means it failed.
Depending on where the red light is, that is where the connection failed, if the red light is on DSL, it means that there is a problem with the server (internet service provider) but if the red light is on INTERNET (authentication failure = router needs to be reconfigure) etc.... to better assist you contact your service provider.

To troubleshoot the issue follow the below steps

1.Try disbaling and enabling the wireless lan card

2.Check whether Ip addresses assigned in the wireless network card.If the address is assigned by dhcp and not assigned in network card means assign static ip in the range supported in the networkand ping the website or gateway.

3.If the ip is assigned already means try pinging the gateway and dns server .If ping is success means the connection between router and pc and internet is good .In that case you have to check whether authentication is successful if any authentication is used.

Depending on the make or router, the internet light may just signify that that an internet signal is detected and not that it is actually authenticated to use the internet. If you can get to the diagnostics or log page of the router and look for 'Chap authentication'. If this has failed then the username and/or password is not being accepted by the ISP.

You need to contact your isp for DNS, see:
Click here!

Currently, there are various ways that ISPs control their users. That is, the WAN IP is provided only when the user is checked as an authorized user. The ISPs currently use three ways: 1. Check if the 'MAC address' is valid 2. Check if the 'Host Name' is valid, e.g., @home 3. Check if the 'User ID' is valid, e.g., RR-Toshiba Authentication Service, RR-Manager Authentication Service, RR Telstra If you are not able to get the Internet IP from the ISP, check which authentication method your ISP uses and troubleshoot the problem as described below.