You can change your all of your apps to https only, and you should... but while you do all of that, here's a kludge that may fix the address search widget until you can get the work done:
1: Find your arcgis_js_api folder that you deployed in your web server.
2: Locate the <version>/js/esri/dijit subfolder.
3: Edit Geocoder.js
4: Replace the text:
5: Save the change, clear your cache, and reload your app and it should work to use the built in arcgisGeocoder again.
Has anyone done that change instead? If so, can you share your settings that worked in the config here?