一大早Cloudflare Tunnel忽然坏掉了。 修复结论：除了检查QUIC协议是否被屏蔽之外，也查一下本机时间同步。

T00:33:53Z INF Retrying connection in up to 1m4s connIndex=0 event=0 ip=198.18.0.134 
2026-01-06T00:33:54Z WRN If this log occurs persistently, and cloudflared is unable to connect to Cloudflare Network with `quic` protocol, then most likely your machine/network is getting its egress UDP to port 7844 (or others) blocked or dropped. Make sure to allow egress connectivity as per https://developers.cloudflare.com/cloudflare-one/connections/connect-apps/configuration/ports-and-ips/ If you are using private routing to this Tunnel, then ICMP, UDP (and Private DNS Resolution) will not work unless your cloudflared can connect with Cloudflare Network with `quic`. connIndex=0 event=0 ip=198.18.0.134 
2026-01-06T00:33:54Z INF Switching to fallback protocol http2 connIndex=0 event=0 ip=198.18.0.134 
2026-01-06T00:35:52Z ERR Serve tunnel error error="TLS handshake with edge error: EOF" connIndex=0 event=0 ip=198.18.0.134 2026-01-06T00:35:52Z INF Retrying connection in up to 1m4s connIndex=0 event=0 ip=198.18.0.134 2026-01-06T00:36:17Z ERR Unable to establish connection with Cloudflare edge error="TLS handshake with edge error: EOF" connIndex=0 event=0 ip=198.18.4.32 2026-01-06T00:36:17Z ERR Serve tunnel error error="TLS handshake with edge error: EOF" 
connIndex=0 event=0 ip=198.18.4.32 2026-01-06T00:36:17Z INF Retrying connection in up to 1m4s connIndex=0 event=0 ip=198.18.4.32

最先想到的是服务商突然屏蔽了QUIC 协议（基于 UDP 端口 7844），准备开始查资料看能否代理。 后来检查中，发现windows时间同步是三天前，手工同步time.windows.com一直失败。 再后来，发现是之前一次代理规则调整不当，造成了时间同步失败。之后本地时间不准确，造成TLS handshake失败。