404. That’s an error.
The requested URL /_/+1/confirm?hl=ja&url=https://houkago.biz/event/12%E6%9C%8818%E6%97%A5%E3%80%80%E3%81%84%E3%82%84%E3%83%BC%E3%82%93%E9%81%95%E5%8F%8D%E3%81%AE%E6%97%A5.html
was not found on this server. That’s all we know.