I'm also having this problem. Intended name is "europeangraphicnovels." (without the period)

I've tried various options, but every time I hit the "create" button, the button shows a small animation, but there's no result or error messages.

If it matters, the intended sidebar text is:

This is a Fediverse community counterpart to the long-running /r/bandedessinee subreddit. "Bandes dessinée" being a term which originally referred to Franco-Belgian comics, but the intent here is to open things up to include any & all European comics, with extra attention paid to graphic novels. Comics from around the world with a 'Euro-style' are also welcome.

Please follow the simple etiquette guidelines of lemm.ee (this instance), and mark all NSFW content in post headers. The designated language here is English, with other language text welcome if it includes context to help make it comprehensible in English.