Common fixes in order: change your DNS to 8.8.8.8 (Google) or 1.1.1.1 (Cloudflare) in your network adapter's IPv4 settings; run ipconfig /release then ipconfig /renew in Command Prompt to force a fresh IP address; log into your router (usually 192.168.1.1) and check the WAN status — you may need to re-enter your PPPoE login details; or check your ISP's outage status page in case it's not actually your equipment at all.

按顺序试：把DNS改成8.8.8.8(Google)或1.1.1.1(Cloudflare)，在网络适配器的IPv4设置里改；命令提示符里运行 ipconfig /release 然后 ipconfig /renew 强制刷新IP；登录路由器(通常是192.168.1.1)检查WAN状态，可能需要重新输入PPPoE账号密码；或者查一下ISP的故障状态页面，说不定根本不是你家设备的问题。