I signed up a few weeks ago. It worked for about a week, until I tried to sign in on a desktop.

I think some number of non-China mobile numbers need verification out of the box. And they've banned most VOIP/Virtual numbers from signing up; you can't use a Google Voice number, for instance.

Then, if you do sign up, there are hair-triggers on "suspicious use." But "suspicious use" means having multiple devices, asking for a password reset, not uploading a profile photo fast enough, or more than a few weeks of non-use.

All of those things are typical for foreign visitors, who don't have Chinese friends to verify them.