How can I test email deliverability to mailboxes protected by Mimecast?

Summary

Testing email deliverability to Mimecast-protected mailboxes involves a multi-faceted approach. Analyzing Mimecast's connection logs helps identify blocked emails and troubleshoot rejections. Correct DNS configuration (SPF, DKIM, DMARC) is crucial. Using tools like Inbox Monster, GlockApps, and Litmus, and seed lists helps monitor inbox placement, considering spam folders. Mimecast's Sender Reputation portal allows checking blocklists. Setting up a personal Mimecast account and using pre-send testing are also valuable. Permitted sender policies can bypass spam checks for critical communications.

Key findings

  • Log Analysis Crucial: Mimecast's logs provide vital insights into deliverability issues, detailing accepted and rejected emails.
  • DNS Configuration Impacts Deliverability: Incorrect DNS records (SPF, DKIM, DMARC) are a common cause of deliverability problems with Mimecast.
  • Inbox Placement Tools Are Useful: Tools like Inbox Monster, GlockApps, and Litmus, along with seed lists, offer comprehensive inbox placement testing.
  • Blocklist Monitoring is Important: Checking the Mimecast Sender Reputation portal helps identify IP or domain blocklisting.
  • Testing Approaches Vary: Approaches range from setting up personal accounts to using pre-send testing and permitted sender policies.

Key considerations

  • Understand Mimecast Logs: Interpreting Mimecast log data requires understanding their terminology and rejection codes.
  • Validate DNS Records Regularly: Regularly validate and update SPF, DKIM, and DMARC records to align with sending practices.
  • Utilize Mimecast-Specific Tools: Consider Mimecast-specific testing tools or a Mimecast account for more thorough assessment.
  • Proactive Reputation Management: Monitor sending IP and domain reputation proactively to prevent blocklisting.
  • Balance Security and Delivery: Carefully configure permitted sender policies, balancing deliverability and security.

What email marketers say
8Marketer opinions

Testing email deliverability to Mimecast-protected mailboxes involves several strategies. Inbox placement testing, using tools like Inbox Monster, GlockApps, and Litmus, helps identify if emails reach the inbox, spam folder, or are blocked. Seed lists can monitor placement at various providers, including those using Mimecast. Analyzing Mimecast's email logs provides insights into delivery issues. Setting up a personal Mimecast-protected account allows direct observation of filtering. Pre-send testing ensures proper rendering across different environments, improving deliverability.

Key opinions

  • Inbox Placement Tools: Tools like Inbox Monster, GlockApps, and Litmus offer detailed deliverability reports and spam filter analysis to assess placement in Mimecast environments.
  • Seed Lists: Using seed lists helps monitor inbox placement across different providers, including those using Mimecast's security solutions.
  • Log Analysis: Analyzing email logs, especially those from Mimecast, provides insights into why emails are being blocked or filtered.
  • Personal Testing: Setting up a personal Mimecast-protected email account allows direct observation of how Mimecast filters your messages.
  • Pre-send Testing: Pre-send testing ensures emails render correctly across different environments, optimizing for better deliverability in Mimecast and other systems.

Key considerations

  • Tool Selection: Choose a deliverability testing tool that specifically supports Mimecast or has a strong presence in the B2B sector.
  • Seed List Accuracy: Ensure your seed lists are up-to-date and accurately reflect the target audience and their email providers.
  • Log Interpretation: Understand Mimecast's log terminology and rejection codes to effectively diagnose deliverability issues.
  • Test Environment Setup: Configure the personal Mimecast-protected account to mimic the recipient's email environment as closely as possible.
  • Rendering Consistency: Optimize email design to ensure consistent rendering across different email clients and devices to avoid triggering spam filters.
Marketer view

Email marketer from Reddit shares that setting up a personal email account protected by Mimecast and sending test emails to it is a good way to see how Mimecast filters your messages. [https://www.reddit.com/r/emailmarketing]

September 2023 - Reddit
Marketer view

Email marketer from Inbox Monster shares that their platform supports Mimecast in their B2B seedlist for inbox testing, allowing users to assess placement within Mimecast-protected environments. [https://www.inboxmonster.com/]

January 2024 - Inbox Monster
Marketer view

Marketer from Email Geeks shares that Inbox Monster supports Mimecast in their B2B seedlist for inbox testing.

April 2022 - Email Geeks
Marketer view

Email marketer from Litmus shares that inbox placement testing helps identify if emails land in the inbox, spam folder, or are blocked entirely by filters like Mimecast. [https://www.litmus.com/]

April 2021 - Litmus
Marketer view

Email marketer from Mailjet Blog explains that using seed lists helps monitor inbox placement at various providers including those using security solutions like Mimecast. Sending to seed list addresses and checking placement helps identify potential issues. [https://www.mailjet.com/blog/email-deliverability-testing/]

February 2022 - Mailjet Blog
Marketer view

Email marketer from GlockApps Blog advises using tools that offer detailed deliverability reports, including spam filter analysis and placement tests, which can help understand how Mimecast and other filters treat your emails. [https://glockapps.com/]

July 2023 - GlockApps Blog
Marketer view

Email marketer from Email Deliverability Forums suggests analysing email logs, and using the logs from Mimecast to understand what may be happening with your emails. [https://www.exampleemailforum.com/]

November 2023 - Email Deliverability Forums
Marketer view

Email marketer from Email on Acid Blog suggests utilizing pre-send testing to check how your emails render in different environments, including those using Mimecast, to optimize for better deliverability. [https://www.emailonacid.com/blog/]

February 2025 - Email on Acid Blog

What the experts say
5Expert opinions

Testing email deliverability to Mimecast-protected mailboxes involves analyzing logs to check for blocks, ensuring correct DNS records (SPF, DKIM, DMARC), and checking blocklists via Mimecast's Sender Reputation portal. Simply verifying mail acceptance isn't sufficient; inbox placement within the spam folder should also be tested, requiring a Mimecast account or an inbox testing tool.

Key opinions

  • Log Analysis: Logs are the primary method for checking if Mimecast is blocking you due to external lists or internal tools.
  • DNS Configuration: Incorrect or incomplete DNS records (SPF, DKIM, DMARC) are a common cause of deliverability issues.
  • Blocklist Monitoring: Checking the Mimecast Sender Reputation portal helps identify if IPs or domains are on blocklists.
  • Inbox Placement: Simply verifying mail acceptance isn't enough; test inbox placement to ensure mail isn't landing in the spam folder.

Key considerations

  • DNS Validation: Regularly validate and update SPF, DKIM, and DMARC records to align with sending practices.
  • Reputation Monitoring: Proactively monitor sending IP and domain reputation to identify and address potential issues.
  • Mimecast Tools: Consider utilizing Mimecast-specific testing tools or obtaining a Mimecast account for thorough testing.
  • Troubleshooting Resources: Look for resources (like a Mimecast deliverability troubleshooting guide) to assist in diagnosing and resolving deliverability problems.
Expert view

Expert from Email Geeks explains that logs are the primary method for checking if Mimecast is blocking you, as they use external lists like Spamcop and internal tools. They also let customers block specific envelope senders and manage settings.

March 2024 - Email Geeks
Expert view

Expert from Email Geeks mentions he's creating a Mimecast deliverability troubleshooting guide for Spam Resource and is looking to connect with someone at Mimecast to improve it.

November 2021 - Email Geeks
Expert view

Expert from Email Geeks explains that simply checking if mail is accepted isn't enough. You need a Mimecast account or an inbox testing tool to see if it lands in the spam folder.

June 2022 - Email Geeks
Expert view

Expert from Word to the Wise responds that you can check if your sending IPs or domains are on any of the blocklists Mimecast uses via their Sender Reputation portal. Monitoring this can help identify if your mail is being blocked due to reputation issues.

October 2024 - Word to the Wise
Expert view

Expert from Spam Resource explains that incorrect or incomplete DNS records (SPF, DKIM, DMARC) are a common cause of deliverability issues when sending to Mimecast protected mailboxes. Ensuring these are correctly configured is crucial.

March 2025 - Spam Resource

What the documentation says
3Technical articles

Mimecast documentation provides several methods for testing email deliverability. Analyzing connection logs in the Mimecast administration console offers insights into accepted and rejected emails. Reviewing bounce-back messages and rejection policies helps troubleshoot delivery problems. Configuring permitted sender policies ensures critical communications bypass spam checks.

Key findings

  • Connection Logs: Mimecast connection logs provide information on accepted and rejected emails, revealing deliverability issues.
  • Rejection Troubleshooting: Checking bounce-back messages and reviewing Mimecast's rejection policies aids in identifying deliverability problems.
  • Permitted Senders: Configuring permitted sender policies allows authorized emails to bypass spam checks for critical communications.

Key considerations

  • Log Interpretation: Understand the information provided in Mimecast's connection logs to effectively diagnose deliverability issues.
  • Policy Review: Regularly review Mimecast's rejection policies to stay updated on potential deliverability blocks.
  • Sender Authorization: Carefully configure permitted sender policies to balance deliverability and security concerns.
Technical article

Documentation from Mimecast explains that connection logs in the Mimecast administration console provide information about accepted and rejected emails, offering insight into deliverability issues related to Mimecast filtering. [https://community.mimecast.com/docs/DOC-1369]

October 2021 - Mimecast Documentation
Technical article

Documentation from Mimecast describes how to configure permitted sender policies, ensuring that authorized emails bypass certain spam checks, which can be useful for critical communications. [https://community.mimecast.com/docs/DOC-1369]

July 2023 - Mimecast Documentation
Technical article

Documentation from Mimecast details steps to troubleshoot email rejections, including checking bounce-back messages and reviewing Mimecast's rejection policies, which can aid in identifying deliverability problems. [https://community.mimecast.com/docs/DOC-1662]

January 2022 - Mimecast Documentation