Sending 200+ mails to hotmail/gmail

Question

I have a website that notifies members for upcoming events by email. I've recently grown to 200 subscribed members and problems are occuring with the mails.

I have a cronjob that handles the mailing so that I can throttle the amount of emails sent. I'm sending 1 email per minute and I still get the error.

I'm sending approx. 200 emails now 2 times per week. Everytime I do a mailing, I get 10-20 bounces saying 'unrouteable address'. Mainly for hotmail and gmail.

I have created my own hotmail address to test this and I'm not receiving any mails from my domain. I'm testing this with a regular webmail client (roundcube).

Any ideas as to why only 10-20 emails don't reach the destination and all the other do?

I'm currently using SwiftMailer on an Exim mailserver (out of my control). The address I'm sending from actually exists and like I said, it's 1 email per minute. The mailing takes approximately 4,5 hours. The bounces occur after 4:22.

Any help is greatly appreciated!

Answer 1

Firstly, Congratulations on having a thriving website!

Secondly, Are you sure the emails actually exist? I have a lot of trouble with 10minutemail emails, Users often sign up with a fake email (or one that lasts for 10 minutes).

Also I've had trouble with sending to Hotmail in the past, their spam controls are ridiculous for admins (but good for users). I have never used swiftmailer, but if its anything like phpsendmail its not going to work with Hotmail or Bt Yahoo address's.

Is the Exim mail server local? If so, you are almost certainly being seen by Hotmail as spam. If your not local, check that your IP is not blacklisted : http://www.mxtoolbox.com/blacklists.aspx

Hope this helps :)

Answer 2

I think the receiving end is simply throttling your traffic based on your ip-address. Your visible ip-address should have a reverse-DNS that gives a reasonable name and that name should again resolve to the same ip-address.

You should check your exim logfiles carefully because there you will find the exact error message that the receiving server gives, and with that information we can better try to solve the problem.