If you are a mail listing provider and send bulk emails every day, of course you don't want your emails are blocked or moved to Junk folder of the recipient mailbox.
To increase the inbox delivery rate of your messages, make sure that all recipients on your distribution lists actually want to receive the mail. Have a look the following sections for some tips on how to make sure your messages are welcomed by most email providers.
Common Rules
Authentication and Identification
                Sign DKIM, DomainKeys with EASendMail.
                Sign DKIM, DomainKeys in IIS SMTP Service and Exchange Server.
            
                Set up DKIM in Exchange Server 2007/2010/2013/2016/2019
            Set up DKIM in Exchange Server 2003
                Set up DKIM in IIS SMTP Service
            
PTR record, or pointer record, enables someone to perform a reverse DNS lookup. This allows them to determine your domain name based on your IP address. Because generic domain names without a PTR are often associated with spammers, incoming mail servers identify email from hosts without PTR records as spam.
You should ask your IP address(es) provider (not domain provider) to set a PTR record for your IP address(es) and we suggest that you use your domain name as the record value.
Subscription and Unsubscribing
Body Format
Realtime Black List
Check if your IP address(es) or linked domain(s) in email body is in realtime black list by the following online tools:
Gmail, Yahoo, Hotmail and AOL Bulk Email Sender Guidelines
If you are sending mail in accordance with above guidelines and still have problems to deliver email to those email providers, you can contact the support by the following URL:
See Also
        Using EASendMail SMTP .NET Component
        User Authentication and SSL Connection
        Enable TLS 1.2 on Windows XP/2003/2008/7/2008 R2
        Using Gmail SMTP OAUTH
        Using Gmail/GSuite Service Account + SMTP OAUTH Authentication
        Using Office365 EWS OAUTH
        Using Office365 EWS OAUTH in Background Service
        Using Hotmail SMTP OAUTH
        From, ReplyTo, Sender and Return-Path
        Digital Signature and E-mail Encryption
        DomainKeys and DKIM Signature
        Send E-mail Directly (Simulating SMTP server)
        Work with EASendMail Service (Email Queuing)
        Process Bounced Email (Non-Delivery Report) and Email Tracking
        EASendMail .NET Namespace References
        EASendMail SMTP Component Samples