Same problem here.
I just signed up with twitter using one of my domains and they're posting this message at the top:
"Is your email address active? We've tried to send emails to '
twitter@ezcg.com', but they are not getting delivered.
Please update your email settings or try sending a message again to your current address."
Doing a test from my email client to any of my domains (eg.
test@slimandbusty.com) reveals none are being forwarded to my gmail account.
I am receiving emails sent to my gmail account that use '
sampleusername@gmail.com'
This might be a different thing. There seems to be an
issue with Twitter. I get the same thing but if I mail the address registered with Twitter it arrives fine.
I have lost emails though. To be honest it doesn't sound like the same problem and I don't want to hijack the thread but I thought I'd mention it just in case there is a bigger issue going on. I've turned off Spamassassin for the time being but that won't be relevant to the original poster if not going through the LP mailserver. I won't know if it's had an effect for a while though.