FAQ #233 (Why do I receive an error message when using my LiveJournal URL as my OpenID identity?) currently only addresses a problem with S1 customizations, even though there are many more reasons why it could be giving an error. A few that come to mind are not being logged in, trying to use an LJ account on LJ itself, and already being logged into the consumer site (although this could be construed as NOP). If it isn't the S1 issue, the user is most likely to come to Support (since there're no fall-through instructions in the FAQ), even though questions about OpenID should be going to lj_dev. I don't want to go into all (read: any) of the the possible errors that could come up, so I propose adding the following line to the end:
If the instructions above do not solve the problem, please post to lj_dev with a detailed explanation of the problem.
That's it. Simple, yet it should do the trick very nicely. Discuss.
Okay, consider this proposal retracted. But I'm going to leave the tags for someone else to change who knows what they're doing.