email ?

Samsung Galaxy A6 email = hotmail. A folder missing from leftside folder list, it was a folder Paul Sellers a wood working forum sending me newsletters. Folder WAS showing in folder list of folder titles, and had added past week several newsletter emails, went to send today's one no folder. All other folders visible except the woodworking one . Saw search up top of email page did search the folder is listed on server how did it get there? Not very good with technology. How to get it back into email folder list?
Many thanks