Spam filters
If you have confirmed that your emails are being created and sent by Smile, but they are not being delivered they may be stopped by spam filters on the recipient end. Whilst you can not control the rules an external spam filter may be enforcing, you can ensure the content of your emails appear the least suspicious or phishy as possible.
Attachments
Particularly large attachments may be blocked by a filter. Or if an attachment passes through a filter it may then be too large for the recipients mailbox. If you have a requirement to regularly send very large files an alternate service to provide access to these files may be more suitable.
Images
Emails that contain only images or a high ratio of images to text may be flagged by a spam filter. Maintaining a good balance of text to graphics will improve the chance that an email is passed successfully.
HTML content
Poorly written or overly complex HTML can identify an email as spam. Emails that contain clear and readable formatting without excessive characters in the layout or excessive inline markup tags will have a greater chance of being read and passed by a spam filter.
Spam trigger words and phishing phrases
Words and phrases that could be blocked vary between filters, but generally spam filters are on the look out for words and phrases that commonly occur in commercial advertisements and promotions or phishing emails attempting to collect personal information. Individual words will generally not trigger a block. The filter will be looking for a high count of these words or phrases in a single email, so avoid or use these words sparingly.
Spam checkers
Downloadable or online spam checker applications provide a method of testing your email content. These tools will analyse your email and report on its deliverability, highlighting any issues that may cause your email to be blocked.
Server blacklists
Use a free online service to check if your email server has been blacklisted. If you discover that your server has been blacklisted you can then take steps to find out why and correct the listing.#