Email Server Tester Tool

Diagnose email server issues and fix email delivery problems. ZeroBounce’s Email Server Tester Tool performs 100+ server health checks, including headers, DNS, SMTP settings, and more.

Try it now - get one free monthly email server health check!

Test my email server

Diagnose email server issues

Take control of your email campaigns and fix email delivery problems fast. The email server test identifies every possible email server performance and configuration issue impacting your campaign and server performance. If you’ve cleaned your list of contacts and are still seeing undelivered emails, your setup may be the culprit.

Optimize SMTP settings, analyze headers, check email authentication alignment, and more.

Header information

Return path

DKIM signature

DomainKey signature

Message ID


and more

RFC-based testing

RFC 2045 (MIME)

RFC 4406 (Sender ID)

RFC 4408 (SPF)

RFC 4871 (DKIM)

RFC 5322 (Message Format)

and more

DNS record checks

MX records

rDNS PTR records

SPF records

Last sending domain

A records

and more

Email port checks

Connection status

Supported extensions

SMTP banner rDNS

SSL Protocol

SSL Cipher

and more

DMARC analysis

RUA check

RUF check

ADKIM test

ASPF test

DKIM test

and more

Additional tests

SPF alignment

DKIM alignment

DMARC check

Author Domain Signing Policy

DomainKeys check

and more

Try Email Server Tester Free

Get a complete email server test now

Benefits of using the email server tester

Troubleshooting email sending issues

Are you cleaning your list with email validation but still experiencing email delivery problems? The issue may be your email server configuration.

The email server tester makes it simple for anyone to get an email server health check. We perform SMTP relay testing, email server compliance checks, and dozens of additional tests for you. Then, we provide actionable solutions to help you improve email deliverability and ensure your emails are reaching their destination.

Improve email server performance

As a business sending and receiving a high volume of emails, your server performance is critical.

Your email server diagnostics identify critical issues that impact the way your server processes emails. Run your test and learn how to improve email server performance like an expert.

No more delivery problems. No more lost emails. No slow delivery speeds. We ensure you can reach your customers by email.

Prevent email spam issues

Email server configuration issues may not stop delivery, but they can cause your emails to go to spam. Issues with email authentication, compliance, or security may cause customer email servers to interpret your emails as untrustworthy content.

The email server test includes DMARC analysis and authentication alignment checks to ensure that your emails are secured and configured correctly and to protect your email-sending reputation from common server configuration issues.

Get more emails to the inbox

Bounced, undelivered emails hurt your email-sending reputation. When your email server performance is compromised, more emails bounce, and more errors occur, which can lead to long-term damage to your company’s email reputation.

Use the email server tester tool to effortlessly perform email server configuration checks regularly and identify issues before they impact your business.

If you notice a high email bounce rate or hear from customers who aren’t receiving your emails, run an email server test to get to the root cause.

How to do email server tests in 3 easy steps

1. Send a test email from your domain

When you open the email server tester tool, we will assign you an email address. Send an email to this custom address from the mail server you need to test.

2. Get your email server health check results

Within minutes, obtain your email server configuration check and email deliverability testing results.

3. Identify and fix email delivery problems

Your email server diagnostics will help you pinpoint warnings and critical settings to fix, enhancing email deliverability.

Do a free email server test now

Get a free email server test every month

Common email server issues

I can’t send emails!

A variety of factors can cause your company’s email delivery efforts to go awry. The culprit could be a failure to optimize SMTP settings, DNS records, MX records, email ports, and more.

Pinpointing the email server issue is as simple as sending an email from your domain with the email server test. Then, we will locate the setting or record the issue and provide you with the fix.

My emails are missing!

Your email delivery service confirms that your outgoing emails are sent. However, your customers and leads aren’t receiving them.

Various email server configuration issues can cause missing emails. If one or two people aren’t receiving emails, it could be a simple storage issue. If reports are more widespread, it can be an issue with authentication records, DNS records, mismatched email ports, or some other problem.

Email server testing is necessary to identify if errors are happening with your mail server or the receiver’s.

My emails are being blocked!

If your emails are being blocked, something’s causing receiving email servers to view your emails unsafe. Are you using best practices for email servers?

All businesses now need to have SPF, DKIM, and DMARC, but it doesn’t take much to misconfigure your policy. You may even block emails from within your own domain!

The email server tester performs an in-depth DMARC analysis and checks for errors with alignment, security, email signing, and additional factors that cause receiving servers to block your otherwise safe content.

But beware - your emails may be blocked if your email-sending reputation declines. Ensure that you’re validating your email list and removing inactive subscribers, as well.

Email server security issues

There’s a reason why receiving email servers won’t trust emails without authentication or mismatched records. Spoofing is more prevalent than ever, meaning your business is a potential target for attackers looking to impersonate you. This is how ransomware attacks that compromise identities online occur.

The email server tester includes email server security testing to identify compliance issues. You want your emails to comply with your policy so that you can feel confident that only trusted senders are using your domain.

Proper email server security configuration will also improve your email-sending reputation and deliverability.

Fix email delivery problems fast

Get a free email server test every month

Additional ways to enhance email deliverability

Email server tests are essential to improve email server performance and boost your inbox placement.

But, even if your test looks clean, here are some additional factors to consider.

Clean your email list — Even a well-configured email server can’t deliver emails to invalid addresses.

Use an email verifier to check your contacts and eliminate any that are invalid or high-risk.

Check email server blacklists — If email delivery issues persist, your domain may be on an email blacklist. Try a Blacklist Monitor to compare your domain against 200+ blacklists, and get alerted any time you’re listed.

Secure your email domain — Email security has always been essential, but now it’s a requirement. Creating email authentication records for SPF, DKIM, or DMARC is free. However, using a tool like DMARC Monitor simplifies the task of creating and enabling records while also providing automated reporting for any suspicious or malicious activity.

Test your email content — When everything else is configured correctly, your email content is the answer. Many mail servers include built-in spam filters that may block your emails based on certain words, phrases, or images in your email. Try an inbox placement tester to compare your email content against popular mail providers before sending.

Try your free email server test now

Don’t lose out on email marketing sales. Use the easy, 3-step email server tester tool and fix email delivery problems like an expert.

Create your free ZeroBounce account - gain access to monthly benefits:

100 credits
Email Validation, Activity Data, Email Scoring

10 Email
Finder Queries

1 Blacklist

1 Inbox
Placement Test

1 Email
Server Test

Try ZeroBounce free

Frequently asked questions

An email server is a communications system that manages how you send and receive emails. There are two primary types of email servers: the outgoing server (interchangeable with Simple Mail Transfer Protocol or SMTP) and the incoming/receiving mail server. Both servers/protocols work together to successfully move a message from sender to receiver.

You can check your email server for free with an email server tester. The tool will check your domain for more than 100 configuration issues and highlight which errors are warnings and which are critical. Your report will also include suggestions on how to correct each error.

After performing an email server test, check your email server diagnostics for any critical issues. Alongside each issue, you’ll find a recommended list of actions you can take to fix the problem. Then, you can run an additional email server test or attempt delivery to confirm that the error has been corrected.

Best practices for email servers include the following:

  • Ensure your MX records point to the correct email server
  • Have a valid Whois record to identify the domain owner
  • Set up a proper return path from undelivered, bounced emails
  • Create a list of approved senders and IP addresses with SPF
  • Encrypt your emails with DomainKeys
  • Create a DMARC policy to monitor sent emails
  • Create rate limits to avoid spam sending and mitigate spoofing attempts
  • Control who can access your server
  • Use sophisticated login passwords with two-factor authentication
  • Use an email server test to track and identify configuration issues

Common email server issues include misconfigured SMTP (Simple Mail Transfer Protocol) settings, which relay email messages between servers. SMTP issues can cause undelivered or missing emails. Additional issues include failed email authentication checks, incorrect or mismatched port numbers, and issues with domain records, such as DNS, MX, SPF, DKIM, or DMARC.