New users not getting registration emails

[Giraffe]

During our recent influx of eclipse watchers and welding enthusiasts, I've received several messages from people who never received the email to complete their registration. I'm hoping to have time later today to dig around in the settings and logs to see if I can figure out why this is happening, but in the meantime would people mind making some socks using new/different email accounts from your mains and seeing if they get said emails? If we can pin down specific email providers or patterns (e.g. brand new email accounts vs. ones you've used for a while), that would help a lot.

Thanks!