xml-rpc broken after the installation of plugin

xml-rpc broken after the installation of plugin
even ifttt stoppedd to working
i used a xml-rpc debbuger (http://xmlrpc.eritreo.it)
and this is the error :
1000002 The RSD document is not well formed. There are characters before the xml preamble.

please how to fix this !

https://wordpress.org/plugins/mashsharer/