My email isn't getting delivered

Question

I've been using the same email address on google apps for years. In the last month or so, some of my emails haven't been delivered to the people I've sent them too. This has been happening when using both Mail.app (via imap) or directly on gmail itself.

I have no idea why this might be happening, maybe some stuff is getting marked as spam? I'm not a spammer... All emails that have been blocked have been personal conversations. The recipients haven't been on the same service either. Some on Gmail, some on mobile me, or even yahoo. Some have been replies, and some have been

How can I track down what's happening? Some important stuff has been missed and it's been frustrating me.

Answer 1

Though online services are off-topic on Super User, this may have a more generic cause: spam filtering based on SPF records, causing receiving email servers to reject your message if your domain has indicated that email should only be sent from certain IP addresses.

You can use some online tools to see if your domain uses SPF records. If it does, then email is best to be sent through the IP addresses listed in those records. So, when using Gmail in Mail.app, use Gmail's SMTP server as well, not your own ISP's server. When your own domain or work email uses SPF (maybe through Google), you might need to use some specific server too.

Online email-based services for testing SPF are available as well.

Apart from SPF: maybe you're using a shared IP address that is somehow blacklisted?