I’ve recently spent a great amount of time on the phone (BT doesn’t seem to answer emails) investigating why outbound emails from an info@ address were all being put directly into recipients’ spam folders by the mail server somewhere out on the web, not by the receiving mail client (Outlook, Thunderbird, etc.). This was amply demonstrated in emails sent to recipients with @btinternet.com email addresses, and it appears that Hotmail and Outlook.com are doing much the same too.
What it boiled down to, having raised a formal complaint with BT due to their apparent disinterest in investigating the problem, is that BT regards all info@ and admin@ email addresses as probable spam senders based purely on the address and their observation that a large proportion of spam comes from such addresses.
Many small businesses use such addresses as their only email address, so this has significant potential consequences for their business communications. Given the numerous people in the UK with @btinternet.com email addresses, the companies cannot send emails from info@ or admin@ addresses to their customers and expect them to appear in the customer’s inbox as would normally occur.
There are anti-spam protocols (Sender Policy Framework (SPF) and Domain Keys Identified Mail (DKIM)) designed to help mail servers authenticate the sending server, but sometimes these are not available from the smaller hosting services for business.
On this occasion my complaint was finally satisfied by having the sender’s address whitelisted in the BT system so that the business’s info@ sending address should not be treated automatically as spam. However, this is not a long-term solution and only affected @btinternet.com recipients, leaving the Hotmail and Outlook recipients needing to trawl their spam folders.
The effective solution is to send from a different email address within the same business domain, e.g. william@, but to set the reply address to come into info@. Thus, the trail of inbound business emails continues, using the published and well-known info@ address, and the outbound messages will be received by the customers.