Just to let you know that everything is back to normal. As expected, LJ thought that the mod account was a spambot... when it was not.
Anyway, I still asked Lyra if she was ok with making a permanent move to Dreawidth (at first, I just wanted to do a backup but well... I don't really trust LJ anymore, as those who follow my personal journal might know), we will keep you updated on the decision.
I will nevertheless make a preventive backup to Dreamwidth tonight when I come back from work, just in case.
Thank you everyone for your patience :)