If this is a member account, please reach out to our support team via our contact page so we can check our 3rd party mailing system’s suppression list (Mailgun). In order to put prevention measures in place, you will need to work with a member of your IT team.

Mailgun blacklists email addresses that bounce their notifications with an error message. They use a standard, by certain error codes, and make exceptions by carefully filtering by words. The general rule is any email with an error of 55x (where x is 0-9) will be added to the suppression list, except if the following words are present:

  • blocklist
  • speed
  • content
  • connection
  • dnsrecord
  • relaying
  • standard
  • codes
  • try timing
  • contact us
  • limit
  • quarantine
  • sender verification failed
  • sender address banned
  • this sender address
  • blocked by
  • banned message data
  • mail banned
  • aol
  • service unavailable
  • service banned
  • banned mxlogic
  • access banned
  • transaction banned
  • transaction failed
  • internal

If Mailgun’s server receives a standard error without any of these words included, you may be added to the suppression list, which we can remove you from manually.

To prevent this from happening again:

  1. Please check with your IT team if they have any strict filters on emails they receive. For example, strict rules around getting emails only from fixed domains.
  2. Please check to make sure your mailbox doesn’t get full, as rejecting incoming mail can flag the address and add it to the bounce list.