@MehdiF you're welcome.
Pity it didn't resolve the issue though.
The dot in your e-mail doesn't matter, it would just be skipped. So if the tenant got created, your tenant would be "xxxmehdigmail.onmicrosoft.com". Since you got the error, that this tenant does not exist, that's most likely a fact. The tenant does not exist. It might have happened, that your subscription got attached to your account in tenant where your account does already exist at (=Vinci-energies). Therefore you do have an azure subscription, but won't be able to sign in due to the policies.
I recommend you to start over again, since it's only an azure free account. When you start creating your azure free account, you can just click on "Create one!" and create a complete new account. As soon as you've got your own tenant and been able to login, you can then invite your xxxxx.mehdi@Stuff .com account to access the tenant and subscription too...
What do you think, does that sound like a plan?
Hope this will do the trick.
If so, please accept this as the answer as a token of appreciation.
Wish you a lovely weekend! :-)