405 Method Not Allowed

I’ve run a dead link checker (https://www.deadlinkchecker.com/) on my site https://wwww.connectis.ca and it reveals an error “405 Method Not Allowed”. I’ve attached the URL and attached the file https://www.connectis.ca/xmlrpc.php The link reference is to my home page https://www.connectis.ca/

What is this error?
Can you repair it?
Do you know if this error does impact my Google ranking.

I am also missing 3 image files please send them to me.
HighendWP/images/prettyPhoto/dark_rounded/contentPattern.png
HighendWP/images/background.png
HighendWP/images/prettyPhoto/facebook/default_thumbnail.gif

Because I don’t know what page is calling these files, it’s easier to place them on my site so the 404 error goes away.