GSMaintenance: Put your site in "Maintenance mode"

[Domi]

Hi,

how can I put some code in the editor; I try something like this but this doesn't work :

<div class="text-center my-4"><img alt="Maintenance" border="0" class="img-fluid screenshot" height="419" src="&lt;?php get_theme_url(); ?&gt;/images/under-construction.png" width="902" /></div>

could be fine to get access to the php function in you plug-in.

any help ?
thanks in advance,
Domi.