An XML file is unreadable.
Posted by Jim Keir on 09 October 2018 12:34 PM
If a plugin complains that it is unable to read XML data, it is almost certainly because the data is damaged. This error message can happen in a number of different places.
If the plugin was downloading data from the web it is possible that it was a temporary network problem. Also possible, and more likely, is that it was a problem with the server that the plugin was communicating with. Either way, please let us know about the error.
Alternatively, if the plugin was reading a file already on your disk, check the contents of that file are valid XML and make any fixes necessary. There are several XML validation tools available online, or as programs you can download and install. Just search for "XML validator".