My suggestion, if you do activities in crypto galaxy. It would be nice, if you using email platform that provider build their email platform based on blockchain technology.
IMO "blockchain technology" is a buzzword & the only real advantage is your encrypted mail is distributed. Asymmetric encryption on email already possible without blockchain technology.
I wouldn't trust any product made by John McAfee, besides while the domain is valid, no one to complete configuration process of their website.