Favicon in browser tab

Version 1.0.7 of YOKO

Favicon not displaying in browser tab. I had successfully done previously and was working using the following steps. Now today it has disappeared:

1. Load favicon.ico file into my directory folder “images” at self-hosted site
2. Insert this css code using editor in the header section under title part:

<link rel=”shortcut icon” href=”https://sitename.com/wp-admin/images/favicon.ico” type=”image/x-icon” />

I’ve cleared my firefox browser history and still not working.
Seems to be displaying in Chrome okay.

Others favicons are showing fine in my firefox browser.
site is debtdebs.com