• You (the sender) send your email via Zoho Marketing Automation (email marketing service)
  
• Scrutinized by spam filters at ISPs, ESPs and anti-spam services
  
• Received by your recipient
  

Spam filters put in place by ISPs, ESPs, and anti-spam services are just one level of security your email goes through before reaching your recipients. Spam filters use different algorithms to check emails for anything phishy and detect unsolicited and untrustworthy emails and prevent them from reaching a user's inbox. Depending on how the spam filters categorize your emails, they may reach the user's inbox, go to their spam folder, or be bounced, rejected, or quarantined. Where your email ends up is largely based on your sending practices, email content, and the recipients' responses to your messages.

Generally, spam filters check sender's activities for any attempts at phishing or forgery. They'll check: 

• Sender Domain
  
• Sender Name
  
• Mailing List
  
• Email Content
  
• Campaign Time and Frequency
  

Sender Domain

Your sender address should be from a valid business domain with a good domain reputation. If you haven't yet authenticated your domain with Zoho Marketing Automation, make sure to do so, as spam filters will be suspicious of emails from an unauthenticated domain. 

Anti-spam services judge a sender domain reputation based on sender's activities and recipients' responses. 

• If this reputation score drops too low, the domain may be blacklisted. We recommend that you regularly check your domain reputation with leading anti-spam or blacklist providers such as  Spamhaus,  Sorbs,  Spamcop, and others.
  


• Domains from public email services such as AOL, Gmail, Yahoo!, or Outlook create a negative impression to spam filters. The  DMARC policy complied by these services discourages using a public domain email address to send emails. As DMARC plays an important role in how spam filters are configured, we recommend you align your sending practices to DMARC policy.
  


• Always send messages using your business domain. A subdomain is fine, but the recipients should be able to recognize the sender easily. For example, if your organization is Zylker then addresses such as patricia@zylker.com or patricia@admin.zylker.com are accepted but manager@zylkero.somedomain.com, or manager@zylker.b.somedomain.com  will be considered to be suspect because the domain is " somedomain.com", not "zylker". When spam filters check the domain name, they'll flag "somedomain.com" as likely to be spam.
  


• Avoid sender addresses like "no-reply@yourdomain.com"  which recipients cannot respond to. This will also appear suspicious to spam filters. 
  

Sender Name

• Too many punctuation marks in the sender name is also flagged as spam. For example, "Patricia" should not be written as "P!!a#tr_i^c$ia. 
  


• Avoid using an email address as your sender name. For example, use "Jim" rather than " jim@zylker.com".
  


• Use the same email address and sender name in all emails because spam filters look for consistency in a sender's identity.
  

Mailing List

The mailing list a campaign is sent to should be hygienic. The leads in the list should be active and interested in receiving the emails. If the list is not cleaned regularly, uninterested leads, and inactive email addresses will add up and will result in a bad reputation with spam filters. This may also prevent the email being delivered to leads who are interested in the emails. You should therefore include list cleaning in your monthly schedule to keep a hygienic list, free from:

• Bounces
  
• Complaints
  
• Spam traps
  
• Unsubscribes
  

Email Content

• URLs to blacklisted domains are suspicious
  
• URLs with multiple redirections are suspicious
  
• Shortened URLs from publicly available services may also harm email deliverability rates.
  

• False promises such as fake coupons
  
• Deceptive subject line and message content
  
• Spammy phrases such as "admin", "security", "payment", "bank", "credit card", "ATM pin", "money", etc
  
• Low quality images
  
• Image-only content
  

The following practices can have a positive impact on how spam filters assess your emails:

• Using text-only content
  
• Correctly maintaining the text-to-image ratio in your email content (40:60)
  

• Sender or company name and address
  
• Phone number, fax number, or contact form
  
• Sender email address
  
• Commercial, cooperative, association, or partnership registration number
  
• Email content creator's name
  
• Tax ID number
  

Campaign Time and Frequency

The time at which you send emails is also important for spam filters. Think about what times your recipients are likely to be annoyed by your emails, and keep this is mind when scheduling.

Spam filters are alerted if anyone attempts to bombard the recipient's inbox. This may even result the sender's domain being blacklisted. Ensure you leave regular intervals between your emails to avoid negative responses from your recipients.

Spam filters also look for:

• Spammy words on your web pages and any sites redirected to from URLs in your email content.
  
• Anything which may resemble phishing in the meta tag information in your email. 
  

Spam filters work intelligently to allow only the most relevant emails to reach the recipients, so engaging and relevant emails aimed at recipients' interests will build a good reputation with spam filters.