Fixed!

[Rancid Roadkill]

Keep getting this whenever I try to trade in my tokens.
Started happening about 10 mins ago.
Update: It's working with different pets, so this is only happening with the Bunny Hamsters in this box.

[Celozon]

It seems to be working fine for me. Make sure you aren't trying to trade in by going back a page after doing a trade in (ie. use the 'Return to the Easter page' link instead). You may also want to try clearing your browser cache and see if that has any effect.

[Rancid Roadkill]

I'm always sure to click 'Return to Easter page' and I just cleared it and it's still showing up the same.
Also tried adopting the pet on my phone and the same issue is still showing.

[lucky333123]

By any chance have you adopted a lot from that particular box?

[Rancid Roadkill]

Yes, about 200 or so.

[Nick]

I've bumped that limit up now so you should be able to trade in.

[Rancid Roadkill]

I didn't even realize there was a limit.
Thanks a bunch, Nick! It's working again!

[Rancid Roadkill]

Thank you lucky333123 and Celozon as well for the help!