my iphone 6 my i pad air and my iphone 4 all say " set up new airport base station when trying to connect to wii fii? what do i do. thanks

I just returned from the USA back to Canada, from hospital. came home and my i phone 6, my i pad air and my i phone 4 will not connect to my wi fi. it is an airport express. My main computer at home still works but all other devices say under the settings/wi fi set up new airport base station. it is not available under under choose a network. thanks in advance for any help. While away I think house sitter may of reset my airport as my security settings says none.