If you are able to successfully send mail to
some, but not others, and the recipients that receive mail successfully
are always the same, then this indicates that the emails are "making it
off the Alentus SMTP Server" okay. That means that, for some reason, the
recipients who do NOT receive mail successfully are blocking your email
for reasons like a spam filter or virus infection.
Do the emails that do not reach the intended recipients have
attachments? If so, then perhaps you should run an up-to-date virus scan
on your system as it is possible that a virus is infecting the
attachments (and then the email is rejected by the receiving system due
to the virus infection).
As far as email being detected as being spam, there are a number of
"triggers" that will cause certain systems to classify an email as being
spam. Some of them are:
- Anything that is "non-standard" text, such as a series of "*"s to separate lines or any other repeating character.
- When the "reply to" address is different from the actual senders
email address (your address), for example: sending mail from
"firstname.lastname@example.org" account and putting "email@example.com" in the
"reply to" address space.
- Not having a subject.
- Using "forbidden" words/phrases including ones like "ON SALE NOW!" etc.
Please check your "signature" line(s), if used, to make sure it does not "violate" any of the above.
Also, it is possible that your email address is being blocked regardless
of your e-mail’s current content. This could happen if a computer that
had your email address stored on it became infected by an email virus.
The virus composes emails using whatever addresses it can find on the
infected computer. It inputs them as the "sender". It is possible that
the systems that do not receive your email are blocking it for this
reason. Check with the receiving systems" administrator and also check
to see that the intended recipients have not put you on a "black list”.
You may also want to try sending mail to an address that you have
previously had trouble with and "ccing" that same email to a temporary
POP account that you first create through the email admin console. Next,
log on using the temp POP account, retrieve the email, and resend it to
the "problem address" - include any "signature" lines that were present
in the original email. If the mail is received successfully, then that
tells you that it is your specific email address being blocked, not the
"content" of your messages.
Please investigate using the "above" information and provide the results to Alentus Support.