Out door tile stains

Hi, I have a large undercover area which has porcelain tiles and I noticed after I pressure cleaned the tiles the cream colour grouting has discoloured in some areas and the edges on the tiles have also slightly discoloured. Could you please give me some advice as to what’s the best method to bring the grouting to it’s original colour and the best product to use to clean the tiles? The tiles are a light fawn colour and being a large area it, it sometimes does my head in. Thanks