So when I last upgraded my web server, PHP, and all the system files there in I failed to take note of ALL THE APACHE AND PHP MODS THAT WERE DISABLED.
I’ve spent about a few weeks trying to track down WHY the WP app and Jetpack were refusing to see the xmlrpc.php file. It was because when I upgraded to PHP7.1, the mod never carried over, so the PHP service had NO CLUE what to do with the request.
# apt search php | grep rpc
php-horde-rpc/artful,artful 2.1.7-2 all
php-xml-rpc2/artful,artful 1.1.3-0.1 all
php-xmlrpc/artful,artful,now 1:7.1+54ubuntu1 all <- Damn You!
php5-xmlrpc/now 5.6.11+dfsg-1ubuntu3.2 amd64
php7.1-xmlrpc/artful-updates,artful-security,now 7.1.15-0ubuntu0.17.10.1 amd64
#apt install php-xmlrpc; phpenmod xmprpc; service apache2 restart
That’s all that was needed. The WP iOS app now sees my sites, as does the WP/Jetpack admin sites. (Which is what I’m using to type this out now)
So remember folks, when upgrading your Linux Distro and all of it’s fine packages, double check your mods when stuff breaks.