Up until recently, all emails sent by the forum were being received by all email services. Now, emails sent to users with Gmail accounts are being rejected. This seems to affect validation emails, password recovery emails etc. Anyone registering with a Gmail account is effectively locked out of the forum. I believe some security changes were made at Gmail on 30th May, the last successful registration via Gmail on my forum took place on 28th May, so I'm guessing this may be the cause. I'm using the PHP method to send emails, so I don't understand why emails that were previously getting through are now being rejected. Is anyone else seeing a larger than usual number of failed registrations?