Missing Email

If you have sent email to a @mailsac.com address or a private domain hosted at Mailsac and it was not received, this document will help you find out why.

@mailsac.com Address

If the address you sent to ends in @mailsac.com and the message was not received it could be because of:

  • The sender has blocked sending to @mailsac.com addresses
  • Large message size. The max message size is 2.5MB
  • Throttling by Mailsac. If you are sending a large volume of email, we may throttle the rate of incoming messages
  • The sending SMTP service has a queue
  • The sending domain, IP address, or receiving address is on the deny list
  • The message may have been marked as spam by the Spam Filter.

Zero-Setup Private Domain (@mydomain.msdc.co)

The Zero-Setup Private Domains handle all MX record changes. You can start receiving email with virtually no setup. If you are still have problems receiving mail it could be because of:

  • Large message size. The max message size is 2.5MB
  • The sending SMTP service has a queue
  • The sending domain, IP address, or receiving address is on the deny list
  • The message may have been marked as spam by the Spam Filter.

Bring Your Own Domain (BYOD) Private Domain

The BYOD Private Domain requires MX record changes. For assistance in configuring the MX records see our BYODomain Configuration.

  • MX Records are incorrect or have no propagated
  • Large message size. The max message size is 2.5MB
  • The sending SMTP service has a queue
  • The sending domain, IP address, or receiving address is on the deny list
  • The message may have been marked as spam by the Spam Filter.

Custom Domain

If you have changed your MX records to use in.mailsac.com and alt.mailsac.com and are not receiving mail. There are several potential causes:

  • MX Records are incorrect or have no propagated
  • Large message size. The max message size is 2.5MB
  • The sending SMTP service has a queue
  • The sending domain, IP address, or receiving address is on the deny list
  • The message may have been marked as spam by the Spam Filter.

Sender Limits

Some services place restrictions on the size, type, rate, and quantity of email that can be sent.

GMail

GMail is not designed for sending bulk mail. The service places limits on the number of emails sent per day and the number of recipients.

SendGrid

Messages sent through SendGrid are often queued and may not be sent immediately.

Sending from a sendgrid.net address may be impacted by throttling. Many Mailsac customers use SendGrid. Until Sender Authentication is configured within SendGrid, emails will be sent from the sendgrid.net domain. Sending from sendgrid.net email address can cause delays in delivery because of the quantity of mail sent from sendgrid.net to mailsac.com. Email sent to a Private Address or a Custom Domain are throttled at a higher threshold. In order to ensure timely delivery it is recommended to configure sender authentication in SendGrid and use a private address or custom domain at Mailsac.

Mandrill

Messages sent through Mandrall are often queued and are not sent immediately.

Request Whitelist

Whitelisting is only necessary if mail delivery is being slowed due to Mailsac throttling. A whitelist request can be submitted using the IP Whitelist Form from the Dashboard.

Whitelisting can be requested for:

  • IP addresses or networks
  • Sending domains
  • Sending addresses
  • Receiving domains
  • Receiving addresses

Spam Filter

Mailsac applies a spam filter to all incoming email.

In the single inbox view, a “spam” label appears in the subject line.

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The Unified Inbox displays messages classified as spam in the “Spam” folder. Spam messages skip the inbox.

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The spam filter can be controlled at an account level.

To disable or enable the spam filter, select Account Settings from the Dashboard and toggle the spam filter setting. This change will only apply to new emails received.

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Contacting Support

The Support Forum is available to all customers for assistance or questions. Customers with email support included in their plan can contact support@team.mailsac.com.

Including the following information will help us identify why you are not receiving mail.

  • the IP address of your sending server
  • the email addresses you are sending to, and/or the domain you are sending TO
  • the from email addresses, and/or the domain you are sending FROM
  • Time frames when messages were lost. A ball park is ok, like, “from 8am - 9am on Dec 3rd GMT we sent 100 messages and only 85 were received” or just “I tried sending 5 messages from 8am - 9am GMT Dec 3rd and none of them went through”