If you try to join an invite-only project, you see a 422 error, which is confusing for users. If someone tries to join an invite-only project (eg https://www.inaturalist.org/projects/tony-s-test/), they should see an error message that tells them it's not possible for them to join, eg
You must be invited to this project in order to join it.
If you try to join an invite-only project, you see a 422 error, which is confusing for users. If someone tries to join an invite-only project (eg https://www.inaturalist.org/projects/tony-s-test/), they should see an error message that tells them it's not possible for them to join, eg