HTTPS Mixed Content Error

Hi Everyone,

I seem to be having a minor issue with HTTPS:

When loading my site i get the Mixed content warning.

Various plugins, URL update’s, htaccess edits, wp-config edits later and the error is still occurring

Chrome points to the error being with the search form (Both admin panel and Main Menu)

Disabling the search icon removes one of the errors

Linux Server

WP 4.9.8

Lets Encrypt Cert

Theme is HITMAG

All plugins on latest updates