The confirmed gotchas from the thread, in order of how often they bite:

```text
the click ID is associated with an Ads account you do not have access to
```

1. Create the conversion goals in the same Google Ads account where the campaigns live. Otherwise you get the click-ID error above. Expected: no account-access errors when importing conversions.
2. Newly created conversion actions can take up to 6 hours before Google lets you import conversions into them. PostHog does not retry failed requests, so wait and use the testing tab to resend events. Expected: imports succeed after the wait.
3. You do not need a gclid filter. The destination already skips events without a valid gclid. Expected: nothing to configure here.
4. If gclid is empty, use a frontend event instead of a backend event, since gclid comes from the browser. Expected: events carry a valid gclid.
5. If you saw 401 'invalid authentication credentials' in early 2025: that was a PostHog environment-variable migration bug, fixed server-side. Users confirmed calls started succeeding again. Expected: no action needed now.

When to use: setting up or debugging the PostHog Google Ads destination.

When not to use: other ad destinations (Meta, TikTok), or Google Ads API problems that have nothing to do with PostHog.

Compatibility: PostHog Google Ads destination. Thread from the PostHog Feature Flags repo.

Variants:
- "posthog google ads destination conversion import"
- "posthog gclid empty frontend event"
- "posthog google ads 401 invalid authentication credentials"

Root cause: mostly setup ordering and account scoping, not one single bug. The 401s were a PostHog-side migration bug.

Edge cases: the 6-hour wait applies per new conversion action. Resend via the testing tab to retry, since PostHog does not retry failed requests on its own.