I know that the issue came from the ‘Site Name’ key. Because it contains a space character in the key. My question is how we can config the header with some special characters such as the space character in column keys.
You need to supply the columns property to control the order and display details of the data property. Make the data property’s keys appropriate identifiers (no spaces). Then, for each column, in the order desired, set columns[nnn].field equal to the column identifier. Then set columns[nnn].header.title to the column name to be displayed. This title may have any characters you like.