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# Find the errors Twig's paying hosts hit – Error Tracking pocket guide

Canonical URL: https://posthog.com/learn/error-tracking/pocket-guide/errors-in-paying-hosts

## On this page

- [What the scout looks at](#what-the-scout-looks-at)
- [The report in your inbox](#the-report-in-your-inbox)
- [The scout itself](#the-scout-itself)
- [Add this to your scout troop](#add-this-to-your-scout-troop)

Twig's hosts pay a monthly fee. This custom scout reports [issues](https://posthog.com/docs/error-tracking/issues-and-exceptions.md) concentrated in paying hosts, even when they rank low by occurrences.

## What the scout looks at

`TypeError: Cannot read properties of null` fired 2,340 times this week on the stays of 31 hosts. Four of them pay for Twig's top plan and get 9% of its traffic, but they carry 71% of the issue, so the scout reports it Fig. 1. An issue spread evenly across hosts gets no report.

Share of the issue = Share of traffic×Concentration

|  | Share of the issue | Share of traffic | Concentration |  |
| --- | --- | --- | --- | --- |
| Issue A | 71% | 9% | 7.9× | Concentrated |
| Issue B | 9% | 9% | 1.0× | Even spread |

Fig. 1 – What the scout saw: four paying hosts get 9% of Twig's traffic. They carry 71% of Issue A and 9% of Issue B, so only Issue A gets a report.

The scout skips issues driven by one browser retrying. The [spikes and stuck loops](https://posthog.com/learn/error-tracking/pocket-guide/spikes-and-stuck-loops.md) scout covers those.

## The report in your inbox

The [report](https://posthog.com/docs/self-driving/reports.md) names the issue and the hosts, with each host's share of the issue next to its share of Twig's traffic Fig. 2.

P11One issue is 71% concentrated in four paying hosts 2Four paying hosts carry 71% of one issue and get 9% of Twig's traffic. The issue isn't in the top ten by occurrences3Scout · errors in paying hosts4ReadyActionable53h ago

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Fig. 2 – The report card in Twig's inbox. The claim is on the card, and the hosts and the comparison are inside the report.Hover over the figure to learn about each element.

## The scout itself

This is a custom scout, and its file is in the [Self-driving pocket guide](https://posthog.com/docs/self-driving/pocket-guide/errors-your-best-accounts-hit.md). With [group analytics](https://posthog.com/docs/product-analytics/group-analytics.md), each `$exception` [event](https://posthog.com/docs/data/events.md) carries the host of the stay. The scout compares each host's share of an issue with its share of Twig's traffic over the last seven days. It checks which hosts pay by their [Stripe](https://posthog.com/docs/data-pipelines/sources/stripe.md) customer ID in Customer analytics. It only reports issues that fired in the last 24 hours. [Querying exceptions](https://posthog.com/learn/error-tracking/pocket-guide/querying-exceptions.md#rank-issues-by-bookings-at-risk) shows the same join. It runs every 24 hours by default and stays quiet unless something needs the team's attention.

## Add this to your scout troop

The scout needs exceptions reaching PostHog, hosts as a [group](https://posthog.com/docs/product-analytics/group-analytics.md), and hosts in Customer analytics with a [Stripe](https://posthog.com/docs/data-pipelines/sources/stripe.md) customer ID on each paying host. The **Add this scout** button in the Self-driving pocket guide opens PostHog with the scout prefilled for review.

[Open the scout](https://posthog.com/docs/self-driving/pocket-guide/errors-your-best-accounts-hit.md)A scout that checks your issues every day and reports the ones concentrated in paying accounts.

See also: [Scouts](https://posthog.com/docs/self-driving/scouts.md) · [Group analytics](https://posthog.com/docs/product-analytics/group-analytics.md) · [Monitor and search issues](https://posthog.com/docs/error-tracking/monitoring.md) · [Self-driving pricing](https://posthog.com/docs/self-driving/pricing.md)