How do I check email deliverability in Salesforce?

1. From Setup -> Enter Test Deliverability in the Quick Find box -> select Test Deliverability.
2. Enter your business email address.
3. Click Send. Salesforce sends a test message from all IP addresses to your business email address. Each test message specifies the IP address from which it was sent.
4. To make sure that you received all test messages, check your business email account.