To resolve this problem, first take a look at what EndNote Web is searching for in the text box between the "Find:" label and the "Search" button. If it is an author and year, in the format of "Smith, 2004", then this is a reference that EndNote cannot locate in your EndNote Web library. If you have changed the author or year for this particular reference in your library, you can type over in the text box to change the search to match your reference, and click on the "Search" button to search for a match. You can search for any part of a reference in this box, even just the author's last name or the year. Any matches will show up below, under the Author, Year and Title columns. If you find the one you're looking for, you can highlight it here and click the Insert button below.

If the text in the box is not an author and year, then most likely this is simply text that was entered between the temporary citation delimiter characters and is unrelated to EndNote Web. In this case, you can click on the "Ignore" button. If there are many of these, you can click on the "Ignore All" button to skip them all at once.

If you are going through the process of locating and inserting the correct references using this dialog, do not at any point click on the "Cancel" button. Clicking "Cancel" will cancel any changes that you have made, and any references that you have inserted in this select matching reference session will be lost. If you need to take a break during this process, click the "Ignore All" button instead, which will skip all the rest of the unmatched citations and format the ones you have inserted.