There are a number of reasons why you cannot see your sign up boxes:
Sign up box not activated
Sign up boxes appears on specific pages
Not supported browser or platform
Sign up box not activated
To activate sign up boxes you need to:
Go to the dashboard
Select the push you want to activate a signup box in
Scroll down in the selected push until you see select sign-up box
Click on select sign-up box and click Save button
Some sign up boxes only appear only specific pages
Once they are activated it is important to note that not all signup boxes are visible on your all the pages of your website:
Price Drop and Back in Stock are only visible on product pages
Delivery Push appears in your customer’s cart page and my account page.
If you do not activate Price Drop and Back in stock sign up boxes,
Welcome Auto-prompt sign up boxes will appear in all product pages of your site.
Not Supported browser or platform
Sign up boxes are hidden from iPad and iPhone devices, but they work on Macs and PCs and all Android devices.
At the moment Firepush does not support Safari, but all other browsers are covered.
To give you an idea of Firepush’s overall near 100% penetration, here’s browser usage stats as of January 2017