“default-icon” not showing on popup after clicking icon

After clicking on the red bell icon, the resulting popup form does not show the default-icon that should be there. Looking at it via the Inspector tool, it should be in the div with a class of “push-notification”, but it is blank. It shows <img src="default-icon">, which should be an actual .gif or something, not just “default-icon”.

How can this be fixed? Thanks for any help.

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