The correct answer is to manually enter the known URL of the captive portal in a web browser. Sometimes devices do not automatically redirect to the captive portal due to a variety of reasons, such as browser security settings, DNS issues, or the device caching an old session. Manually entering the portal's URL can often bypass these issues and allow the user to authenticate. Checking the Wi-Fi signal strength is less likely to be effective because the device has already connected to the Wi-Fi network, indicating adequate signal. Disabling and re-enabling Wi-Fi may not address the underlying issue of the captive portal not prompting. Updating the device's drivers is an unlikely solution for the described scenario and would not directly address the issue of reaching the captive portal page.