Invitation refused: Email is not allowed for this email provider. Please use another address."

[Pierre_CARLI]

Thank you for your answer, Jammy.,
But it is not the case:

And by the way, I can no longer invite any kind of email, whatever the domain …!
Over the last months, I used to invite people without any problem (we are more than 70 members).
I don’t know what has happened?

Thanks again for you help.