--- title: "Apollo Deliverability: Diagnose List and Sending Problems" description: "An email-deliverability problem should be investigated across list quality, sender configuration, targeting and campaign behavior." canonical_url: "https://www.leadpipe.com/blog/apollo-deliverability-cliff-2m-sends/" source_url: "https://www.leadpipe.com/blog/apollo-deliverability-cliff-2m-sends/" md_url: "https://www.leadpipe.com/blog/apollo-deliverability-cliff-2m-sends.md" content_type: "article" pubDate: "2026-04-02T00:00:00.000Z" last_updated: "2026-09-12T00:00:00.000Z" --- # Apollo Deliverability: Diagnose List and Sending Problems Quick answer An email-deliverability problem should be investigated across list quality, sender configuration, targeting and campaign behavior. This guide does not report a two-million-send experiment or establish that Apollo deliverability has declined. An email-deliverability problem should be investigated across list quality, sender configuration, targeting and campaign behavior. This guide does not report a two-million-send experiment or establish that Apollo deliverability has declined. This is a Leadpipe-authored buying guide. Product statements are based on the linked vendor references; evaluation steps are recommendations, not reported test results. ## Start with the observed failure A bounce, a spam placement and a lack of replies are different outcomes. Collect the sending-system evidence and the campaign’s target definition before blaming the data supplier or increasing volume. | Symptom | Evidence to inspect | | --- | --- | | Hard bounces | Address status, source and validation timing | | Wrong-person replies | Employer and role freshness | | Spam complaints | Targeting, permission, message and suppression | | Low positive replies | Relevance, offer and timing | | Inconsistent performance | Sender, cohort and time-period differences | ## Keep the data and execution questions separate [Apollo](https://www.apollo.io/pricing) combines research and engagement. Record which system supplied the contact and which sent the message. Review a representative sample for current role, employer and required fields before changing tools. Do not use an open-rate change alone as proof of inbox placement or buyer intent. Compare delivery failures and substantive replies, keeping the population and time window explicit. Label sample limitations. ## Change one part of the process at a time Pause inappropriate targeting and honor suppression immediately. For the remaining approved campaign, make a documented change and compare comparable cohorts. Changing list source, sender, copy and volume together makes the result difficult to interpret. Our [Apollo alternatives guide](/blog/apollo-alternatives/) can help with a supplier shortlist after the failed requirement is clear. [Apollo pricing](/blog/apollo-pricing/) covers the cost of the selected workflow. A new data source does not remove the need for responsible targeting and sender operations. ## Where Leadpipe fits Leadpipe supports both account-level and person-level workflows. Its [IP to Company API](/product/ip-to-company/) retrieves stored company information from an IPv4 or IPv6 address; its separate [Identification product](/product/identification/) supplies eligible visitor records and activity. Choose company context for account research and person-level output when the action requires a specific visitor. A company lookup returns no people or visits. Confirm API eligibility and its separate lookup allowance in the [official documentation](https://docs.leadpipe.com/ip-to-company/introduction). Person-level coverage is strongest in the US. EU/UK traffic defaults to company-level identification; person-level requires affirmative consent. Fields can be missing, so judge required output on your actual traffic. If you need research signals from outside your website, evaluate [Orbit](/product/orbit/) separately and check its audience allowances. The [current pricing page](/pricing/) lists Pro 500 at $147/month for 500 identification credits. The trial is **7 days or 500 profiles, whichever comes first, no card**. Confirm the delivery and data-use requirements of your chosen plan. Use the [vendor evaluation kit](/resources/visitor-identification/) to record the same acceptance criteria for every candidate. [Start a Leadpipe trial](https://dashboard.leadpipe.com/auth/signup) when website identification is the requirement you want to measure. ## Related decisions Browse the [comparison directory](/compare/) for alternatives and head-to-head guides. Use the [software buying guide](/blog/b2b-website-visitor-identification-software/) to define requirements and the [person-versus-company guide](/blog/person-level-vs-company-level-visitor-identification/) to interpret identification results. ## Related vendor guides - [Apollo Alternatives for Prospecting and Sales Workflows](/blog/apollo-alternatives/) - [Apollo vs RocketReach: Prospecting or Contact Lookup?](/blog/apollo-vs-rocketreach/) - [Apollo vs UpLead: Prospecting Workflow and Data Quality](/blog/apollo-vs-uplead/) ## Sources and review basis Published by Leadpipe. Vendor references support product descriptions; recommendations reflect our assessment of fit. Confirm current plan and contract terms before buying. - [Leadpipe IP to company API](https://docs.leadpipe.com/ip-to-company/introduction) - [Apollo product / buying reference](https://www.apollo.io/pricing) - [Leadpipe product / buying reference](https://www.leadpipe.com/product/identification/) - [Leadpipe pricing and plan allowances](https://www.leadpipe.com/pricing/) [Explore all comparisons and our evaluation method →](/compare/)