Yes, remote subscription form. What I saw that was the error in some screenshot you had was that the 'acct:' part was included, which makes the lookup fail. Without it, it works even with underscores.
If it for some reason still doesn't work for you, maybe it's because you're on #quitter.se
and because @hannes2peer
unfortunately has to work to gather capitailst money to pay for crappy capitalist stuff in a crappy capitalist society I think it drains energy from maintaining stuff too often (is my projected interpretation).