# Blocklists and Link Reputation > Inbox providers may distrust a sender because of the sending IP, domain, email delivery service account, or links in the email. - Human page: https://mailrith.com/guides/blocklists-and-link-reputation - Markdown page: https://mailrith.com/guides/blocklists-and-link-reputation.md - Category: Authentication and Deliverability - Reading time: 6 min read - Related keywords: Blocklists and Link Reputation, Blocklists and Link Reputation guide, Authentication and Deliverability, Authentication and Deliverability guide, email sending guide, email marketing guide, email deliverability guide, Dedicated and Shared Sending IPs, Tracking Domains Links and UTMs, Google Safe Browsing Site Status ## 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 Mailrith free tool, pair that specific free-tool result with the relevant issue or step section from this guide. ### Blocklists and Link Reputation Inbox providers may distrust a sender because of the sending IP, domain, email delivery service account, or links in the email. A blocklist is a list that marks IPs, domains, or URLs as risky. Some blocklists are public. Others are private systems used by mailbox providers, security tools, or company gateways. Blocklists are not the only reason email lands in spam, but they can be a strong signal. Delivery can suffer when a sending IP is on a serious blocklist, a domain is linked to malware, or a URL shortener has poor reputation. Link reputation matters because inbox providers check more than the From address. If your email links to unsafe domains, excessive redirects, suspicious tracking links, or pages that trigger browser warnings, the message may be treated as risky. A shared IP can be affected by other senders on the same email delivery service pool. A dedicated IP makes your own traffic more responsible for the IP reputation. A domain can also carry reputation separate from the IP. Do not respond to a spam-folder issue by randomly changing links, domains, email delivery services, and content at the same time. First identify what changed: sender domain, email delivery service, IP pool, list source, campaign volume, link domain, landing page, or complaint rate. The best long-term protection is simple but effective: authenticate properly, send wanted email, avoid risky links, keep landing pages clean, and monitor errors from your email delivery service. 1. If delivery suddenly drops, check whether the issue affects all inbox providers or only one. 2. Check your email delivery service logs for blocklist, policy, reputation, or unsafe-link errors. 3. Check whether any linked domain shows browser warnings or safe-browsing warnings. 4. Avoid public URL shorteners and unclear redirects in important campaigns. 5. Use branded, stable domains for links and landing pages when possible. 6. If the sending IP is listed, ask the email delivery service whether the IP pool is shared or dedicated, and ask what remediation they recommend. 7. If your domain is causing the issue, pause high-volume sends and review permission, complaints, link destinations, and recent site security problems. 8. After you fix the cause, send again to a smaller engaged subscriber group before sending to the full list. - Blocklists can apply to IPs, domains, URLs, or email delivery service infrastructure. - Private mailbox reputation systems matter even when public blocklist checks find no listing. - Link domains can affect delivery, especially when they look unsafe or use many redirects. - Do not use random link shorteners for bulk campaigns. - Switching email delivery services will not fix a poor list, unsafe links, or misleading content. - Check [Sender Reputation and Spam Rate](https://mailrith.com/guides/sender-reputation-and-spam-rate.md) before assuming the issue is only technical. ## Fix Common Issues ### Confirmed Blocklist Listing An email blacklist checker found a usable blocklist listing response for one or more sending IPs. 1. Pause broad sends from the affected sender while you identify the cause. 2. Open your email delivery service logs and look for recent complaints, bounces, spam traps, compromised credentials, or policy errors. 3. Review recent list imports and remove old, purchased, scraped, or uncertain addresses. 4. Fix the sending cause before you request delisting. 5. Use the blocklist owner's removal process only after you fix the cause. 6. Resume sending with a smaller engaged subscriber group and watch bounces and complaints closely. ### Blacklist Result Is Inconclusive An email blacklist checker says the response depends on the DNS resolver, or a blocklist returned an open-resolver or public-resolver limitation response. 1. Do not treat the public-resolver warning as a confirmed listing. 2. Open your email delivery service's reputation or deliverability dashboard. 3. Ask that email delivery service whether the sending IP is listed from the resolver the service uses. 4. Check your mail server logs if you manage your own SMTP server. 5. If active mail is being rejected, use the exact SMTP rejection text to identify the blocklist or mailbox provider involved. ### No Confirmed Blocklist Listings An email blacklist checker did not find confirmed listings on the public blocklists it can query. 1. Keep the email blacklist result in context because mailbox providers also use private reputation systems. 2. If delivery is still poor, review bounces, complaints, recent volume changes, and link reputation. 3. Check your email delivery service logs for private policy blocks or mailbox-specific reputation messages. 4. Avoid changing email delivery services or domains unless you know the current root cause. ### Invalid Blacklist Target An email blacklist checker cannot recognize the input as a valid domain or IPv4 address. 1. Enter a sending domain such as `example.com`, not a full URL. 2. If you have a specific sending IP, enter only the IPv4 address. 3. If your domain is only a tracking or landing-page domain, use the actual mail-sending domain or IP instead. 4. Run the check again after you clean the input. > A blocklist is usually a symptom. Fix the cause before you ask for delisting or move to another email delivery service. Related resources: - [Dedicated and Shared Sending IPs](https://mailrith.com/guides/dedicated-and-shared-ips.md): Understand how shared and dedicated infrastructure affects reputation. - [Tracking Domains, Links, and UTMs](https://mailrith.com/guides/tracking-domains-links-and-utms.md): Understand how tracked links and link domains affect trust. - [Google Safe Browsing Site Status](https://transparencyreport.google.com/safe-browsing/search): Check whether a domain has browser safety warnings. ## Related Guides - [Sender Domains and Email Authentication](https://mailrith.com/guides/sender-domains-and-authentication.md): Your sender domain is what inbox providers learn to trust. Authentication proves that your email delivery service is allowed to send email for your domain. - [From, Reply-To, and Return-Path](https://mailrith.com/guides/from-reply-to-and-return-path.md): An email can include several sender-related addresses. Each address has a separate role for delivery, authentication, or replies. - [DNS, PTR, and Reverse DNS](https://mailrith.com/guides/dns-and-reverse-dns.md): DNS records identify your domain. Reverse DNS helps inbox providers check that a sending IP address has a valid hostname.