Each time an user register on my website, I will use php mail() to send a single email for authentication.
Recently I found out that, a lot of yahoo and hotmail users are not activated their accounts, lets say upon 1000 users, only 200 are activated. I am curious, and I try register using my hotmail account. To my surprise I didn’t get the activation email.
Is my domain being blocked from sending email?? How to solve this problem? I tested my others email account (my company and gmail), it works fine. I think only yahoo and hotmail give me problems!!
Please help, its been few days, I have lost a lot of potential customers, I don’t want to lose it anymore!!
Are you on shared hosting? Someone from within your shared hosting network had probably abused yahoo and hotmail with spam at one point so they were either blocked or they are being thrown into their junk folders.
‘snickn’ has part of the right idea but I’ll assume that you’ve done that already or you wouldn’t be asking.
K. Wolfe’s point about shared hosting is another reason to use dedicated hosting: You generally get your own clean IP address that hasn’t been tainted by spam filters declaring the IP address as a spam source. IMO, if you are running a business, dedicated hosting is the only option that makes sense.
I’ve personally found that the mail() function with plain-text only e-mail seems to have issues with deliverability even if you’ve done due diligence on correct DNS and host setup. The closer you can mirror standalone e-mail clients (e.g. Outlook, Thunderbird), the less likely the e-mail will get flagged as spam and accomplishing that with the mail() function is pretty hard to do. Actually, sending e-mail that gets through spam filters is quite difficult, which is why I built a nearly complete SMTP/POP3 library for that purpose (it is roughly 1MB in size and can emulate all major e-mail clients). I personally get near-100% deliverability for one-off e-mails on everything that uses the library - not even close with the mail() function. The code is available at the website in my signature if you are interested.
Microsoft relies on senderscore.org scores to determine whether your IP address is a spam source or not for Hotmail. I’ve found Sender Score to not only be wildly inaccurate but if you sign up for an account, they’ll spam you for their services - irony at its finest.