registration email

Hello ??
I have troubles with registration email. Some subscribers receive it and others don’t. For some people, in the back office, the payment by paypal don’t appear. I know that they have subscribed only with mail by paypal. And others, it works. There payments appear and they receive the registration email with the link to subscribe…I don’t understand why.
(Sorry for my poor english)
Thanks a lot for your help ??
Emmanuelle

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