Email deliverability can feel unpredictable, especially in the early stages of warm-up or when sending patterns change. Small fluctuations often cause concern, but not every dip in inbox placement or spam appearance indicates a serious problem.
This article explains the most common technical mistakes that impact deliverability, helps you understand what behavior is normal, and clarifies when action is actually needed.
Seeing some emails land in spam does not automatically mean something is broken. During warm-up, email providers are still learning how to classify your sending behavior, and occasional spam placement can be part of that evaluation.
Normal behavior may include:
A small number of emails landing in spam early on
Fluctuations in inbox placement from day to day
Temporary spam placement that resolves without changes
Concerning behavior is different. Consistent spam placement across multiple providers, increasing spam rates over time, or sudden drops after configuration changes usually signal an underlying issue that needs attention.
Early warm-up is a testing phase for email providers. They observe volume patterns, engagement signals, and authentication consistency. During this time, it’s normal to see mixed results as providers calibrate trust.
Positive early signals include stable sending, gradual volume increases, and improving inbox placement over time. Negative signals often appear when sending behavior changes abruptly or when authentication is incomplete or misaligned.
Many deliverability issues come from small technical oversights rather than major failures. These mistakes often go unnoticed but can quietly reduce trust.
Common issues include:
Missing or misconfigured SPF, DKIM, or DMARC records
Sending from a new domain without sufficient warm-up
Running multiple sending tools from the same mailbox
Ignoring daily sending limits or provider throttling
Making frequent changes during warm-up
Each of these can confuse provider algorithms and slow down reputation building.
Email providers value consistency. Even small changes—such as increasing volume too quickly, pausing and restarting warm-up, or adding a new sending source—can temporarily reduce trust.
These changes are not always harmful long-term, but they often cause short-term deliverability dips that recover once behavior stabilizes.
Not every issue requires immediate action. If spam placement is occasional and does not worsen over time, monitoring is usually sufficient. Providers often self-correct as they gather more data.
Action is recommended when:
Spam placement increases consistently
Deliverability drops across multiple providers
Authentication checks start failing
Sending errors or throttling messages appear
In these cases, reviewing recent changes and pausing sending increases can prevent further damage.
Anxiety-driven changes often make deliverability worse. Frequently adjusting volume, switching modes, or restarting warm-up can interrupt progress and extend recovery time.
Staying consistent, patient, and observant is usually more effective than reacting to short-term fluctuations.
Most deliverability issues are gradual, not sudden. Understanding what behavior is normal helps prevent unnecessary changes that can slow progress. Real problems tend to show clear patterns, not isolated incidents.
By avoiding common technical mistakes and allowing warm-up to progress naturally, deliverability improves steadily over time