This kind of behavior is usually programmed to happen when the remote system receives a lot of requests from your IP address. Since ISPs do not allocate the same public IP to more than one customer at a time, except for mobile connection, it is most likely coming from something in your home.
If you don't notice the problem on other sites, you should contact the site to double-check with them why it happens.
Otherwise, if you're on a mobile connection, you could contact your provider to get a public IP, but they may refuse or charge more for it. If it's not a mobile connection, then most likely one of your devices is doing a lot of requests to that site and you should look into that. It could be caused by many things including spyware or simply your family using the site abundantly.