If presented with XML validation errors like the following, you can use the possible solutions below to quickly fix the validation.
Error: Table parsing error that contains text like:
xref: validity error : IDREFS attribute rid references an unknown ID "box2" Document
ID table1 already defined table-wrap: validity error : ID table2 already defined element xref:
validity error : IDREFS attribute rid references an unknown ID "box1" xref: validity error : IDREFS attribute rid references an unknown ID "box2" Document
Examining the issue in the XML:
When encountering these issues, you'll be able to look into the XML to get a better idea of where the problem is occurring. For example, if the error message says "ID table2 already defined." You can look for "table2" in the XML by hitting CTRL+F. This may show you that id="table2" is incorrectly being used by the wrong table. At that point, you have identified the table which is rendering the incorrect table id and can start formatting the text around the table.
The majority of these issues are all correlated to some type of discrepancy in the formatting of the tables in the document or the text immediately around them.
Possible Solution 1: Copy the formatting of any similar formatted tables that appear before or after the above mentioned table with errors. Copy the content from the error table into the copied version of the table and save. You should also make sure the tables are setup as actual tables with proper rows within the document. If the tables are vary too much in rows, columns or are this is too time consuming, see solutions 2 and 3.
Possible Solution 2: Check if the TITLE of the table or box is not displayed DIRECTLY on top of it. Even if there are a few spaces, it can throw off the conversion script and the system will try to assign it’s own ids to the tables in sequential order. Remove any spaces between the title of the box or table and this should be resolved. Another good way is to copy the title of a table which is not throwing an error and paste it onto the table with issues. Then re-write the title of the table as it was. This will take on the formatting of the table title that works.
Possible Solution 3: Copying from Word and pasting the tables and their title into Libre Office, then removing any spaces between the title and the starting of the table, then copying and pasting the contents back into Word seems to fix this issue at times.
Error: Some headings or text aren't appearing in the PDF and/or the html files are showing headings with strange nested divs/ul/ol. <sec> tags for those headings are missing in the XML file.
Possible Solution 1: The headings in the document may be incorrectly formatted as a bulleted list (even if not visible as a list). You can click on each heading and make sure the bulleted list icon in the home toolbar of Word is not highlighted, if it is, click it to remove the list formatting from the heading.
Error: DTD error such as:
Element list-item content does not follow the DTD, expecting (label? , (p | def-list | list)+), got (disp-quote )
Possible Solution: Change the italic item to non-italic in the document.
Error: Refcheck not parsing references.
Possible Solution: Make sure that the "References" heading before the reference list is appropriately named. Sometimes it may be named "Bibliography" or there might be incorrect spelling or incorrect characters somewhere around the heading. Remove it and make sure there is space between the content on top as well. Please also make sure the heading is also formatted as a actual heading in the word processor.
Error: Figure Caption Errors Such as:
IDREFS attribute rid references an unknown ID "ref"
Possible Solution: Make there the figures in the submission do not have multiple items being referenced in a single square bracket. Example: [4, 5, 6]. Only a single reference can be used:  else the error above will appear.