BT Mail overview

BT is one of the world's largest providers of telecommunications services and solutions, with operations in more than 170 countries.

Infrastructure

Deliverability best practices and troubleshooting support

• Ensure you follow BT's best practices.
• Use opt-in permission methods for all subscribers. Do not purchase email lists or engage in list harvesting from third-party websites.
• Have a list hygiene strategy in place to remove or suppress unknown and unengaged users from your email list.
• Use a consistent From and friendly-from address to make it easier for subscribers to identify your email.
• Configure all IPs with valid reverse DNS (PTR) records.
• Authenticate all email with SPF, DKIM, and DMARC.
• Do not use a dynamic IP address. Send email to BT from a dedicated or shared IP address.
• Implement a prominent unsubscribe link in all email with a one-click unsubscribe process and immediately honor all unsubscribe requests.
• Deploy different mailstreams (e.g. transactional and marketing mail) from different IP addresses and From addresses . 
• BT relies on content-based filtering.
  • Make sure the message subject line matches the message content.
  • Use a combination of images and text in your email as BT does not display images by default. Be sure your email can be understood with images turned off. Image-only email is likely to be filtered as spam.
  • Send content your subscribers want to receive. A high number of subscribers deleting your email without reading or marking them as spam causes delivery issues.
• Monitor SMTP response codes closely for clues on delivery issues.
  
  • According to BT, senders fixing problems surfaced by their SMTP response codes "have no problem sending email to BT customers".
• BT does not disclose which blocklists are used in filtering decisions, but you should ensure that your IP addresses and domains are not listed on any important blocklists.

Mediation

• Send an email to postmaster@btinternet.com for delivery issues. Be sure to include a summary of the issue, you sending IPs, domains, SMTP error messages, and any steps taken to correct the issue.