converting html closing tag to xhtml closing tag

I face with below error once I use confulence

Error parsing xhtml: Unexpected close tag </xml>; expected </br>.n at [row,col {unknown-source}]: [1,329]

I figure out the problem stems in closing tag .For example it doesn’t accept <br> as a closing tag it accepts <br/> as a right closing tag.
So I looking forward to find a way convert self html closing tag to xhtml closing tag.