V5 and V6 marriage isn't working?

Ok, I know there's a topic about this already. But I would like someone to help because this has been an ongoing problem. I have a v5 and V6. They are at the age where they can visit the dating show/matchmaker. I have connected them a bunch, and on the v6 it shows the 4 happy faces and on the v5 the happy music house thing. Those are the highest friendship levels to my knowledge. I connected them more after that just to check.

Every time I look how to marry them up, I see the same thing. High friendship levels, put v5 on connecting, marry then give. However, when I try to select give it just gives me the denying noise, the kind you get when something is unavailable. I've even tried pressing accept and connecting but they just shakes their heads.

I switched out my v5s battery (it was kinda old). My v6 is pretty current. Does anyone know what I'm missing here?

Here's my little reference: https://www.tamatalk.com/IB/topic/163511-tamagotchi-ultimate-connecting-guide/page-1

How old are they? If they are under 6 they may be too young to marry. I hope this helps!

One is 8 for sure. I pause them a lot but it's been over a month so they're at least a week old.