Hello! The password belongs to someone else, right? In other words, your code is free, including domain name server and so on. It doesn't matter if you trade or not. In fact, there is a lawyer's letter saying that there is infringement, so there should be related matters. First of all, you need to know where the source code of your website comes from, and then give the lawyer's letter to a lawyer who is close to you and trustworthy to verify the authenticity. If there is real infringement, this seems a bit serious. If you defend your rights, it is estimated that you will lose a lot of money. I remember that the trademark of Baidu input method was infringed by sogou input method at that time, and Baidu lost hundreds of millions, so you should be careful!