WP HTTP Error: The certificate issuer's certificate has expired. Check your system date and time.

WP HTTP Error: The certificate issuer's certificate has expired. Check your system date and time.

This XML document is invalid, likely due to invalid characters. XML error: Reserved XML Name at line 3, column 38

A feed could not be found at http://bokukanonikki.com/feed/. A feed with an invalid mime type may fall victim to this error, or SimplePie was unable to auto-discover it.. Use force_feed() if you are certain this URL is a real feed.