3DS not connecting to internet (off and on?)

My 3DS (I've had it for about a year) is connecting (connection test) to my router fine, but then loses connection then the connection comes back and so on and so forth. It gives me the error message 3-2001, and I looked it up on Nintendo's website, followed the instructions, but it still didn't work. I have connected it to other (unblocked) connections, and it works fine, but I guess that means it's my router. Any advice?

could be your broadband, check the connection with another device, if it's fine on said device, could be something wrong with your 3DS, ie the wireless has broken

if the connection is not fine on your other device, then you may want to try getting a different broadband

It's neither of those, my 3DS WiFi works connected to other connections, just not this one. And my wireless is fine because I use it for my laptop, iPhone, and Xbox.