Utilize email authentication
Even if you set an email address belonging in the site domain in the From field, spammers can still send spoofed mail as if you sent it from your domain. As long as the possibility of email spoofing exists, the risk of mail service providers confusing your legitimate mail for spoofed mail remains.
To protect your mail from this risk, you can utilize email authentication methods including SPF and DKIM, which are supported by most major mail service providers. For detailed instruction about how to set up authentication methods, consult your provider’s support.