posthog-common-errors

# PostHog Common Errors ## Overview Diagnosis and solutions for the most common PostHog integration errors. Covers event capture failures, authentication issues, feature flag problems, identity fragmentation, and SDK initialization errors. ## Prerequisites - PostHog SDK installed (`posthog-js` or `posthog-node`) - Access to browser console or server logs - PostHog project API key (`phc_...`) available ## Instructions ### Error 1: Events Not Appearing in Dashboard **Symptoms:** `posthog.capture()` calls execute without error but events never show in PostHog Activity tab. **Diagnoses and fixes:** ```typescript // Problem A: Not flushing in serverless/scripts // posthog-node queues events — they're lost if process exits before flush const posthog = new PostHog('phc_...'); posthog.capture({ distinctId: 'user-1', event: 'test' }); // FIX: Always flush before exit await posthog.shutdown(); // or await posthog.flush() // Problem B: Wrong API host posthog.init('phc_...', { api_host: 'https://app.posthog.com', // WRONG — this is the UI }); // FIX: Use the ingest endpoint posthog.init('phc_...', { api_host: 'https://us.i.posthog.com', // CORRECT for US Cloud // api_host: 'https://eu.i.posthog.com', // For EU Cloud }); // Problem C: Ad blocker blocking posthog-js requests // FIX: Set up a reverse proxy (see posthog-sdk-patterns) // next.config.js rewrites: /ingest/* → us.i.posthog.com/* // Then: posthog.init('phc_...', { api_host: '/ingest' }); ``` ### Error 2: Feature...