My guess is possibly a sales solicitation from ANSL in trying to get you register domains with them. As for the 'network keyword', I have no idea. The only thing applicable for a domain registrar would be the actual domain name ie "Company.com". There is no 'network keyword' that I know of, and I've registered many domain names over the years.
Unless of course some words got mixed up in the translation between Cantonese and English.
I think you're safe to ignore and delete the message since you already own the domain name you want to keep.