Why are my emails being rejected by bb.go.th and marked as spam?
Summary
What email marketers say11Marketer opinions
Email marketer from Email Geeks shares that the response code suggests it is from a Fortinet email security gateway and suggests checking if the URLs in the message are listed as malicious on Fortiguard.
Email marketer from EmailToolTester shares that being listed on a Real-time Blackhole List (RBL) can lead to email rejections. Suggests checking common RBLs to see if your sending IP is listed.
Email marketer from Gmass mentions that failing to properly warm up a new IP address can make emails get flagged as spam. A gradual increase in volume is recommended.
Email marketer from HubSpot explains that using a dedicated IP address, rather than a shared IP, gives you more control over your sending reputation, which can improve deliverability.
Email marketer from Litmus shares that emails that do not render correctly across different email clients can be seen as suspicious and can increase spam scores.
Email marketer from SenderVerify shares that a high complaint rate (users marking emails as spam) can negatively impact sender reputation. Suggests implementing feedback loops to monitor and address complaints.
Email marketer from Mailjet explains that spam filters often flag emails based on content. Using spam trigger words, excessive capitalization, or poorly formatted HTML can lead to rejections.
Email marketer from Email Geeks shares that the response indicates the rejection was about the message contents, not the IP address. They then ask for further detail about which stage this is occuring.
Email marketer from Reddit shares that the domain bb.go.th may have strict filtering policies, and a low sender reputation (IP or domain) can lead to rejections. Suggests checking sender reputation tools.
Email marketer from StackOverflow mentions that failing SPF, DKIM, or DMARC checks can cause emails to be rejected. Suggests ensuring these authentication methods are correctly configured for the sending domain.
Email marketer from Email Marketing Forum explains that sending to invalid or inactive email addresses (resulting in bounces) can damage sender reputation. Recommends regular list cleaning.
What the experts say3Expert opinions
Expert from Word to the Wise (Laura Atkins) explains that rejections from specific domains like bb.go.th could be due to internal blocklists or filtering rules at the recipient's organization. It's not always a public RBL causing the issue. Suggests direct communication with the recipient's IT department to resolve the problem.
Expert from Email Geeks explains that the email might be blocked due to an internal block, not necessarily a publicly accessible blocklist.
Expert from Spam Resource (John Levine) explains that many systems use reputation to filter spam. If your sending IP or domain has a poor reputation (due to past spam activity), your emails are more likely to be blocked or marked as spam. He has mentioned the importance of maintaining a good sending reputation and monitoring blacklists.
What the documentation says4Technical articles
Documentation from Fortinet explains that emails can be rejected by their FortiGuard email security gateway if the URLs in the message are listed as malicious, leading to a spam classification.
Documentation from RFC Editor explains that 5xx SMTP error codes indicate a permanent failure. Specifically, 554 errors often relate to policy rejections or content filtering issues on the recipient's server.
Documentation from Google Postmaster Tools explains that a low sender reputation, especially when sending to Gmail users, can cause filtering issues and potential rejections by other domains as well.
Documentation from Microsoft explains that Exchange Online Protection (EOP) uses various filtering techniques, including IP reputation, domain reputation, content filtering, and user complaints, to identify and block spam.