Actually I got this error when I tried to setup Windows Live Writer (WLW) to publish on my blog.
“An error occured while connecting to your weblog : Server error…, 403 forbidden…”
I googled for the solution but only in vain, because I didn’t understand what they are telling. Those solutions are too complicated because they involve editing .htaccess files of your web-host.. blah.. blah.. blah…
At last I found a solution which is very simple. I found this solution at Scribefire help guide. I am sharing this work around with you as I think this may be helpful to you. To solve XML-RPC problem see below steps :
1. Copy and paste this in browser URL http://<your-site-name>/wp-admin/options-writing.php
2. If wordpress asks you to log in, then log in using your username and password.
3. After logging in, under the Remote publishing category enable XML-RPC option and save changes. For more assistance then see image below.
That’s it. This is solves the XML-RPC problem.
NOTE : This work around is only for wordpress. So, i’m not sure whether it works with other CMS platforms.