Your snippet needs to be installed on all relevant pages in order to display any type of notification.
For example, if you have configured a notification to display on https://mywebsite.com/pricing, make sure your snippet is installed on that page.
Use one of the two testing methods described below:
ProveSource Debug Tool
You can use our debug tool: https://help.provesrc.com/en/articles/3485826-provesource-debug-mode
Use Browser Console
Open your browser's console by hitting the Ctrl+Shift+J (or Cmd+Shift+J on a Mac) and find the ProveSource debug lines: