Shopify changes sender email addresses to protect its ecosystem from abuse, enhance deliverability, and combat phishing and spam, complying with evolving ESP and Yahoogle policies. This occurs when domains aren't properly authenticated, harming sender reputation. To resolve this, users must correctly configure SPF, DKIM, and DMARC records in their DNS settings, authenticating their domain and authorizing Shopify to send emails on their behalf. This ensures emails reach recipients' inboxes, builds trust with email providers, and improves overall email deliverability. Failure to do so results in Shopify reverting to its generic sender email.