EmailEmail
These guides cover mail on your own domain: creating mailboxes, connecting Outlook, Apple Mail or a phone over IMAP and SMTP, and setting the DNS records that decide whether your mail arrives or lands in a spam folder.
If your mail is being delivered to spam, the answer is almost always SPF and DKIM rather than the message itself. Those records tell receiving servers that your mail is genuinely authorised to come from your domain, and without them a legitimate message looks exactly like a forged one.