ESET mobile antivirus activation failed

[Guest Silicon x]

I installed ESET mobile antivirus . Then , after agreeing user content , I gave my email in it (in the option of select your email address).After then when i clicked next , it checked and displayed that    "Communication failed . license cannot be used for this product". I tried with my another Email account also but it showed the same answer . 

Note: I want to use the free version and trail version.

Hoping for the best solution .

thanks .