Most Likely Cause and Fix
Your markup contains a table that either:
is being used to layout a form and contains form elements in the wrong place
contains invalid markup
Avoid using table for layout.
Refer to previous errors regarding elements contained within the
<table> and fix these.
What This Error Means
This error is telling you that the validator reached the end of a
<table> element and found that this element
did not contain what is expected.
This can happen if you inadvertently include an empty element which should contain child elements or if the markup within the element is not valid.
How To Fix It
There is no straightforward common fix for this type of error as it depends on the element that raised the error and the context in which this element appears in your markup.
Refer to the line and column number in the specific error you encountered to get some context on the cause of this error.
Check that you haven't included an element and omitted required child elements, such as including a list that lacks list items.
Check that the markup within the relevant element is valid. You may find that the relevant element contains additional elements that are not correctly nested or are not included within required containing elements.