Sorry the instance was accidentally left with “registration approval” mode instead of open registration. I changed that now and approved all registrations.

Its fine to use this instance for testing, however it needs to run in allowlist mode, because it runs on a small vps and with open federation quickly gets completely overloaded from the large instances. So let me know your test instance domains and I will add them. Best message via https://lemmy.ml/u/nutomic or @nutomic:matrix.org otherwise I might not see it.