How to Solve Hotmail Deliverability Problems with Salesforce

Emails sent from Salesforce to Hotmail, Outlook.com and Live.com addresses sometimes vanish without reaching the inbox or even the junk folder. The fix is to send them through a mail provider with a good reputation, such as SendGrid or Mailgun, using SMTP Relay.

Why Outlook.com filters Salesforce email

Outlook.com runs the mail for hotmail.com, live.com and outlook.com addresses, and its filter is stricter than most. It weighs the reputation of the server a message comes from heavily. Salesforce sends from servers shared by every org on the platform, so your email arrives with a reputation you don't control. Even large, legitimate senders have been caught by this.

How to recognise it

The usual sign is silence. Recipients on Hotmail or Outlook.com addresses say they never received the email, it isn't in their junk folder either, and Salesforce shows it as sent. Other providers, such as Gmail, deliver the same message without trouble.

The fix: send through a provider with its own reputation

Providers such as SendGrid and Mailgun maintain their sending reputation with Outlook.com as their core business, and give you a support team when something does get blocked. Office365 works too: your email then leaves from Microsoft's own infrastructure. Salesforce cannot log in to these providers by itself; SMTP Relay sits in between and does that for you. Setup takes ten to twenty minutes:

• Integrate SendGrid with Salesforce
• Integrate Mailgun with Salesforce
• Integrate Office365 with Salesforce
• Integrate any SMTP server with Salesforce

What else to check

Set up SPF and DKIM for your domain, keep your recipient lists clean, and make sure your messages have a plain-text part. A better sending server fixes reputation problems, not content problems. For the wider picture, see why Salesforce emails end up in spam.