My question is simple: How does the puppy predictor work? I've been trying for a bunch of time and yet I never manage to get it to work at all. Or is it like... disabled?
Which part of it is givin' ya trouble? One of the least intuitive things about it that sorely needs attention is that if you change anything about your wolves, say their sex, any markings, etc, and then try to save them to use for the predictor, they will come up as "Custom" rather than their name, and then they will NOT interact honestly with the generational checker that tells you if two given wolves can breed or not.
The only workaround available to check same-sex pairings is finding an opposite-sexed offspring of theirs to check in their stead, if at all possible, or to check the relatedness of THEIR parents and the parents of the other dog you want to breed them to. Extremely tedious!
If that isn't the problem, and it's more of a website-not-loading correctly issue, it may be a great idea to make a bug report that details as much of the issue as possible. Fixes don't happen terribly often here, but it can help document ongoing issues and if it's something possibly caused by a specific device or browser, other people may be able to help you troubleshoot that better as well.