go to the database from the hosting and empty the table of the language that is giving 404 errors. like this for exemple: wp_trp_gettext_es_es or if french is bad this: wp_trp_gettext_fr_fr…this solved an entire language with 404 errors for me. the table regenerates itself….beware of not deleting the tables. do a backup of the database before doing this.. Hope it helps
