I am using Excel for Office 365 ProPlus. And I'm trying to create an XML file from Excel data (not more than 100 rows).
Started with the following sample schema file:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<data-set xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<record>
<LastName>Smith</LastName>
<Sales>16753</Sales>
<Country>UK</Country>
<Quarter>Qtr 3</Quarter>
</record>
<record>
<LastName>Johnson</LastName>
<Sales>14808</Sales>
<Country>USA</Country>
<Quarter>Qtr 4</Quarter>
</record>
</data-set>
And it worked on a sample data file:

Now I'm trying the same schema on an extract from my real data (though in fact I will need a more sophisticated schema with 2 layers - see below):

Now I'm getting an error: "...is not exportable because it contains the following: A mapped element relationship with other elements can't be preserved".
I may be blind but I can't see any principal difference between two sources. I've tried copying formatting, remapping from scratch, renaming the columns to no avail.
Does anyone have an idea of how to make it work?
BTW, my desired schema will look similar to this one:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<data-set xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<Graduate>
<HUSID>1600000000003</HUSID>
<OWNSTU>8936</OWNSTU>
<COUNTRY>XF</COUNTRY>
<EMAIL>[email protected]</EMAIL>
<FNAMES>Diana</FNAMES>
<SURNAME>XYZ</SURNAME>
<UKTEL>02080000000</UKTEL>
<UKMOB>07700000000</UKMOB>
<PostalAddress>
<ADDRESSLN1>36 Street </ADDRESSLN1>
<ADDRESSLN2>London</ADDRESSLN2>
<ADDRESSLN4>United Kingdom</ADDRESSLN4>
<POSTCODE>HA7 HA7</POSTCODE>
</PostalAddress>
</Graduate>
<Graduate>
<HUSID>160000000013</HUSID>
<OWNSTU>8936</OWNSTU>
<COUNTRY>XF</COUNTRY>
<EMAIL>[email protected]</EMAIL>
<FNAMES>Ana</FNAMES>
<SURNAME>LLL</SURNAME>
<UKTEL>02089999999</UKTEL>
<UKMOB>07777777777</UKMOB>
<PostalAddress>
<ADDRESSLN1>36 Park ,</ADDRESSLN1>
<ADDRESSLN2>London</ADDRESSLN2>
<ADDRESSLN4>United Kingdom</ADDRESSLN4>
<POSTCODE>HA7 HA8</POSTCODE>
</PostalAddress>
</Graduate>
</data-set>