# Protect List Quality > A smaller list of people who want your emails is better than a large list that ignores or rejects them. - Human page: https://mailrith.com/guides/protect-list-quality - Markdown page: https://mailrith.com/guides/protect-list-quality.md - Category: Setup and Permission - Reading time: 4 min read - Related keywords: Protect List Quality, Protect List Quality guide, Setup and Permission, Setup and Permission guide, email sending guide, email marketing guide, email deliverability guide ## AI Agent Notes - Use this page as plain-language guidance for the specific email sending issue named in the title. - Preserve the distinction between Mailrith, an email delivery service, DNS, and inbox providers when explaining fixes. - When a user is running a free tool, pair the tool result with the relevant issue or step section from this guide. ### Protect List Quality A smaller list of people who want your emails is better than a large list that ignores or rejects them. It is tempting to think a bigger list always means better results. In email, that is not always true. A small, active list can be healthier than a large list full of old, inactive, or risky addresses. Inbox providers watch subscriber behavior. If many people ignore, delete, [bounce](https://mailrith.com/guides/bounces.md), or [complain](https://mailrith.com/guides/spam-complaints.md), future emails can become harder to place well. This is why list quality is not just a reporting metric. It affects delivery. - Remove imported addresses that are obviously invalid before sending. - Use tags or custom fields to remember where a subscriber came from. - Avoid sending every campaign to every subscriber by default. - Keep bounced, complained, unsubscribed, and blocked subscribers out of normal marketing sends with [Suppression Lists and Subscriber Status](https://mailrith.com/guides/suppression-lists.md). - Consider re-engagement campaigns for inactive subscribers before removing them from regular sends. ## Fix Common Issues ### Invalid Email Address A checker found missing parts, extra `@` signs, spaces, invalid dots, excessive length, or an invalid domain format. 1. Do not guess the correction unless it is obvious and verifiable. 2. Remove accidental spaces, trailing punctuation, or copied display-name text. 3. If the domain or local part still looks wrong, ask the subscriber for the correct address. 4. Keep the invalid row out of active imports until it is corrected. 5. If many rows have this issue, fix the signup form or import source before collecting more addresses. ### Email Domain Typo A checker found a domain that looks close to a common mailbox provider, such as `gmial.com` instead of `gmail.com`. 1. Confirm the suggested correction before changing subscriber data. 2. If the address came from a form, ask the subscriber to re-enter or confirm it. 3. Correct only the rows you can verify. 4. Keep unverified typo rows out of broad sends because they can bounce or reach the wrong person. ### Disposable Email Addresses A checker found temporary or disposable mailbox domains that are often abandoned. 1. Avoid importing disposable addresses into normal campaign lists. 2. If the address is important, segment it separately and avoid large-volume sends. 3. Use double opt-in or account verification for forms that attract disposable addresses. 4. Review the signup source if many disposable addresses arrive from the same form or campaign. ### No Addresses Found A bulk checker could not find any email-like values in pasted text or an uploaded file. 1. Paste one email per line or copy the email column from your spreadsheet. 2. If uploading a file, use CSV or TXT. 3. Make sure the file contains actual email addresses, not only names or IDs. 4. Try a small sample first, then upload the full list after the format is confirmed. ### Duplicate Addresses A bulk checker found the same normalized address more than once. 1. Keep the first clean occurrence of the address. 2. Remove repeated rows before importing. 3. If duplicate rows have different tags or fields, merge the useful data into one subscriber record. 4. Check the import source so the same person is not collected multiple times again. ## Related Guides - [Prepare the Sender Identity](https://mailrith.com/guides/prepare-sender-identity.md): The sender name, sender email, reply-to address, and verified domain should match the trust you want subscribers to feel. - [Keep Permission and Compliance Simple](https://mailrith.com/guides/permission-and-compliance.md): Send to people who expect your email, identify yourself clearly, and make leaving easy. - [SMTP, APIs, and Email Delivery Services](https://mailrith.com/guides/smtp-and-delivery-providers.md): An email delivery service is the sending engine, and Mailrith connects to it through service APIs or SMTP.