confirmation email not working

Hello,
I searched the forum without finding the answer I was going..
When a member registers on my site receives an email to confirm their account
It works fine but sometime overnight it no longer works.
I do not touch anything so I do not know or it comes from.
Before I reported my concerns to my webmaster who was involved
Today I no longer have a webmaster and I do not know how to resolve this concern.

Members no longer receive mail send site (e-mail confirmation, request password, notification ...)

What can I do?

Hello 

1. You need to check Trach and Spam folders in your mailbox. May be your mail server marked Dolphin's notifications as spam and therefore you cannot see them.

2. Dolphin uses default PHP mail function to send messages. If you didn't change anyting and didn't install any new modules then you may try to contact with your hosting provider. May be they made some changes in mail server settings.

1. Yes I did check the spam there is nothing.

2. Ok I'll see what the next, because I did make no changes

I'll let you know if I have an answer.
thank you

This morning I restarted the server and everything works coorectement
Thank you anyway

I have the same problem, my email stopped working. What change in server PHP configuration would stop email from working?

Dan