Why am I getting an "Authentication" Failure & how do I fix it please?

[Android Central Question]

Hello I need some expert advice here please....I've been trying to fix this for days. I'm running Android 7 with modem "Fritz!Box 6490 Cable". When I try wireless I keep getting "Authentication" failure so obviously no internet .
So on a guide at https://forums.androidcentral.com/ambassador-guides-tips-how-tos/326698-guide-troubleshooting-wi-fi-connection-problems.html
....."3. See if the router’s security is interfering. ......."
having tried everything else I momentarily switched off all security on the modem and everything worked...connected! When I then tried all the separate protocols...back to same problem. On a Windows 10 rig, internet no problem. Now that I know its a security problem, what's my next step? I'm going nuts here, any help much appreciated

 

[B. Diddy]

On the router? Worth a try.

 

[T Clarke]

Didn't work, same problem. I rang Vodafone, they insist it's a password problem and told me to do a factory reset again. Aaargggghhhh!

 

[anon(10614692)]

Anything here that helps? https://en.avm.de/service/fritzbox/...nnot-establish-a-connection-to-the-FRITZ-Box/

 

[B. Diddy]

Is the wi-fi password you're using very simple? As a test, make sure there aren't any special characters or capital letters in it.

 

[T Clarke]

Anything here that helps? https://en.avm.de/service/fritzbox/...nnot-establish-a-connection-to-the-FRITZ-Box/

the solution lies in changing the name of SSID.
From the link......Adjusting the name of the Wi-Fi network (SSID)
1. Click "Wi-Fi" ("Wireless") in the FRITZ!Box user interface.
2. Click "Wi-Fi Network" (or "Radio Network") in the "Wi-Fi" ("Wireless") menu.
3. Disable the option "Different names for the Wi-Fi networks on 2.4 and 5 GHz" (or "Different names for the radio network on 2.4 and 5 GHz"). This way, the FRITZ!Box uses the same name for the 2.4 GHz and 5 GHz frequency bands and can steer wireless devices into the frequency band that is ideal in the given situation ("band steering").
4. • Enable the option "Name of the Wi-Fi network visible" (or "Name of the wireless radio network visible"). This way, all wireless devices can establish a connection to the FRITZ!Box and the FRITZ!Box can optimally control wireless devices in the Mesh ("Mesh Wi-Fi Steering").
5. • Enter a unique name in the field "Name of the Wi-Fi network (SSID)" or "Name of the wireless radio network (SSID)". This prevents your wireless devices from trying to connect to the wrong wireless router if there are Wi-Fi networks with the same name in the area.
6. • Click "Apply" to save the settings. All Wi-Fi connections to the FRITZ!Box are cleared when the new Wi-Fi network name is adopted. You must then reconfigure the Wi-Fi connections to the FRITZ!Box.

Many thanks

[EDIT] Sorry, I made a huge mistake in my last entry & I can't edit. The proper solution was to give both bands a seperate SSID

 

[B. Diddy]

Glad you figured it out! That's interesting though -- oftentimes it's the opposite issue, i.e. having the same SSID for both 2.4 GHz and 5 GHz bands can cause confusion for the device trying to connect. I guess the FRITZ!Box has special firmware for that.

EDIT: I merged your subsequent post to your main solution post where you corrected yourself and said that you had to create separate SSIDs for the 2.4 GHz and 5 GHz bands. Now that makes more sense to me!

 

[Kizzy Catwoman]

I had to do the same with my Netgear router. Had to separate 2.4 and 5Ghz bands