Emails sent via Email not received by certain adresses

[eluser]Unknown[/eluser]
Hi,

i am using the email class on a page currently in development and witnessed some weird behavior.
The email sending works just well, when sendig to my gmail adress or one of my adresses with custom domain everything is received.
But there are adresses with custom domain which do just not receive the mail - there also seems to be no spam filter which is blocking the mail. (Manually sent emails are received normally).

I am using the 'mail' - protocol.

Any ideas what could be the reason?

Thanks

[eluser]CroNiX[/eluser]
It could be lots of things, including domain reputation, blacklists, missing headers, lack of DKIM, no PTR record, etc. Email delivery is an art, and not guaranteed. What works for one host might not work for another. This is why there are companies who only specialize in email deliverability, such as returnpath, sendgrid (which is what this forum now uses) and many others.

It could also be going to a spambox instead of the inbox, even if there isn't a "spam filter".

[eluser]Abel A.[/eluser]
Do the emails bounce? or are they simply not showing up?

[eluser]skunkbad[/eluser]
If you are sending mail from a shared host, and if the email address in your "from" does not have the same domain as the one used by the server to send the email, your email may not be delivered.