Error: 404 Not Found

Sorry, the requested URL 'http://u.limo/wp-admin/admin-ajax.php?channel_id=social_wechat&action=xh_social_channel&tab=login_redirect_to_authorization_uri&xh_social_channel=eae32193e9&notice_str=8554748511&hash=0f24469fd14d1befb02c0803e6e45a57&redirect_to=https%3A%2F%2Fu.limo%2Ftag%2F%25E6%2597%25B6%25E5%25B0%259A%25E8%258A%2582%25E5%25A5%258F%25E4%25BA%25A7%25E5%2593%2581%25E4%25BF%2583%25E9%2594%2580%2F' caused an error:

Not found: '/wp-admin/admin-ajax.php'