Using the PubMed XML export plugin, I am able to export the XML file. However, testing the file on https://www.ncbi.nlm.nih.gov/pmc/tools/article-previewer/ any file I run fails.
What is confusing is the error messages are say that there are undeclared tags, which are in the file. For example, and
ERROR: ERROR :[2018-03-06 14:19:21]: -:8: element JournalTitle: validity error : No declaration for element JournalTitle
Does the export plugin not actually work?