It says to me trying to duplicate the request via the tool I made one day ago in the old thread:

"You cannot submit a moderation request because you must have email authentication turned on and your account must be at least 1 month old. To turn on email authentication, visit your account Settings."

I've been the moderator on several games for a long time now and it's always been enabled. Is this the option it's talking about, here?

https://imgur.com/a/IY0mnZL

If so, it's again enabled.

It doesn't say that for me

Go to your settings and hit "save", that may resolve the issue for you.

Yeah, that solved it. I couldn't request before that, but I guess that's the answer. Thanks @ShikenNuggets. :)