Make sure they are facing towards eachother If it doesn't work, reset your tamagotchi will a sharp tool (most preferred, a pencil) and press 'Download.' Do it to both tamagotchis in case it is both causing the problem. Try connecting again, and hopefully it will work
Well you know on the v3's where the V3 and the others sign is well click that on the V3 and for the V4 you have to do the same thing scroll down on your tama and find where it says others and then press the middle button down.
If you were wondering how to try to get them to connect well you have to go to that little heart in the last row and press that on both tama's
I'll do it step by step, even though you probably already know this: go to the heart icon on both of your Tamas. Select "other" for both of them. They should say "standby." While they still say "standby," press B again, and it should say connect. Just hold your tamas so the IR parts are facing each other. I hope it works!