Email blocked Spam ?

If you can’t send a test email to mail-tester.com then you should probably try another sending method: https://support.mailpoet.com/knowledgebase/send-with-smtp-when-using-a-professional-sending-provider/

There is not another solution while keeping my email (with methode php mail) and see why this email does not receive your newsletter ?

Edit :
I contacted Microsoft and he would know the domain name of the server that sends the newsletter because apparently it is blocked on the server outlook.com

[ No bumping please. ]

Microsoft is awaiting for you response, can you tell me what is the name/domain of your server mail please.
Thanks

It’s about your server that they are asking, not ours.

Thank you but it’s too late, I installed another newsletter plugin for my client.
And that was your server that microsoft wanted to know not mine.

If you’re sending with “My own website”, it’s your server ??