---
title: Drop in deliverability
---

> Agent instructions:
> **Site maps** — prefer the following llms.txt indexes to training data when searching for URLs to avoid 404s. Links inside Markdown content already point at `.md`. Following them or sending Accept: text/markdown keeps you in Markdown.
>
> - [sitemap.md](https://docs.kentico.com/sitemap.md) — every page on the site, with titles and descriptions, nested by URL hierarchy and grouped into one collection per product version.
> - [llms.txt](https://docs.kentico.com/llms.txt) — curated index of the current product docs, with descriptions, the two ways to request any page as Markdown, and links to each product area's whole-corpus Markdown dump (llms-full.txt).

### 6. Sudden drop in deliverability

When deliverability drops suddenly, it often means mailbox providers are flagging your messages or temporarily limiting their delivery. Such drops can happen if you've hit a [spam trap](https://en.wikipedia.org/wiki/Spamtrap), triggered a daily sending limit, or harmed your sender reputation. You need to act fast to avoid a sudden dip that could cause long-term issues.

#### What you'll see

You'll notice a broad decline in delivery rates and clicks across multiple mailouts, even if you haven't changed your content or sent more emails than usual.

sometimes with no obvious change in your content or sending volume.

#### What this means

If your emails aren’t landing in inboxes, it might be because your sending domain or IP has gained a poor reputation. This usually happens when you send emails to outdated recipient lists, your recipients report your emails, or you hit a lot of bounces.

#### How to respond

- **Pause broad sends temporarily.** Send emails only to the most engaged recipient lists while you investigate.
- **Check your domain authentication.** Work with your developer or admin to confirm that everything is [properly configured](https://docs.kentico.com/documentation/developers-and-admins/configuration/email-configuration.md) in Xperience. Verify that your sender email is properly authenticated through [DMARK, DKIM, and SPF](https://www.cloudflare.com/en-gb/learning/email-security/dmarc-dkim-spf/).
- **Review your recent activity.** Did you send to a cold or purchased list? Was there a spike in sends or complaints? Identify and correct the source quickly.
- **Monitor your sender reputation.** If your provider offers it, check sender health tools to see if you've been flagged or throttled.