Only get Bad Request from POST /api/v1/signinattempts

This not the right Category but did see one for just the API; figured this was closest. GET /api/v2/auth/introspect works perfectly but when I switch to POST /api/v1/signinattempts it fails. The Reference says there is no other parameters. If I try GET /api/v1/signinattempts I obviously get a method not allowed. So what am I missing?

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Referrer: forum-search:https://1password.community/search?Search=API%20sigininattempt