R6120 Repeatedly gives error message when attempting to set up the guest network

[thejohnsolo]

Just updated the firmware which caused the router to factory reset itself. When I got everything back up and running, I tried to turn on the guest network. Every time I do, it gives me an error message after trying to set up the credentials. I’ve rebooted (even unplugged) several times. Still getting the same error message.

[FURRYe38]

What error message are you getting? 

What happens if you use the default SSID name and a PW of Password123? 

[plemans]

Something to keep in mind with the R6120 is that it isn't gigabit. Its only 10/100mbps.

Most ISP's base level speeds have increased to over 100mbps speeds. Meaning if that's happened with you, the R6120 is bottlenecking your network and slowing you down. Its a pretty old/base model device. 

[thejohnsolo]

It doesn't give an error code. It just says "Configuration Error" and on the bottom it says, "The Router could not apply your new settings. Check your WiFi connection and try again." I have tried the default SSID, but not that password. Any ideas?

[thejohnsolo]

My ISP has increased our speed to 300, but does that mean that the router would have a problem with activating the guest network? If so, is there a way to fix it? 

[plemans]

You should still be able to activate the guest network. 

but if you have 300mbps service, you need to upgrade that router. 

Its not capable of speeds over 100mbps as its not gigabit. Its bottlenecking your network big time. 

[michaelkenward]

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@plemans wrote:

but if you have 300mbps service, you need to upgrade that router. 

Its not capable of speeds over 100mbps as its not gigabit.

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For clarification, this is a reference to the wired LAN and WAN ports on the router. It has nothing to do with wifi speeds.

The manual says it all, well it would if it didn't have a mistake.

When it says:

LAN Four RJ-45 ports supporting 10BASE-T
WAN One RJ-45 port supporting 10BASE-T

it is actually 100BASE-T. (100 Mbps) That is slower than your Internet connection.

Newer routers have 1000BASE-T. (Even newer one are faster still.)

Even without an Internet connection, nothing on your network can travel through your router faster than 100 Mbps.

The surprise is that Netgear even sold devices as slow as this as recently as 2019.