Why did the email go to spam?

Why did the email go to spam?

In terms of the credibility of the sending email address

If a sent email goes to a junk mailbox, it may be because the sending mailbox has a low reputation or has been identified as a spammer. Email service providers use a variety of algorithms and filters to determine whether an email is spam, including an assessment of the sender's reputation. If the sender's mailbox has been associated with a record of spamming or other bad behavior, this may result in their email being classified as spam.

From the recipient's habit of using the mailbox

It may be the recipient's mailbox settings or personal preferences that cause emails to be placed in the spam folder. Some users may have set strict filtering rules that require specific types of emails to be placed directly into the spam folder to minimize spam interference. In addition, some users may not be interested in campaign promotion emails from an e-commerce website or have unsubscribed from that website, which may also result in the recipient marking the email as spam or putting it directly into the spam folder.