Enable and configure notfoundpassthrough

config/core.extension.yml

@@ -91,6 +91,7 @@ module:
   multiparagraph_flow: 0
   mysql: 0
   node: 0
+  notfoundpassthrough: 0
   options: 0
   page_cache: 0
   paragraphs_browser: 0

config/notfoundpassthrough.settings.yml

@@ -0,0 +1,12 @@
+servers: 'http://archive.experienceolympic.com'
+search: ''
+redirect: ''
+site_404: ''
+title: null
+content: null
+save_redirect: 1
+redirect_code: '302'
+force_redirect_code: 0
+_core:
+  default_config_hash: 03kQa0BMwNSDV8ceb2SnCSEQRmeCqoEwbdtN-QZfBRY
+langcode: en

config/system.site.yml

@@ -7,7 +7,7 @@ mail: tours@ExperienceOlympic.com
 slogan: ''
 page:
   403: ''
-  404: ''
+  404: /notfoundpassthrough
   front: /node/8
 admin_compact_mode: false
 weight_select_max: 100