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.
Authentication and Identification
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
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:
Using EASendMail SMTP .NET Component
User Authentication and SSL Connection
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