3439032 - UI5 applications are not shown in SAP Cloud Portal Service with "sap_horizon" theme

• Apps renders for an instant but then a blank screen is displayed.
• "sap_horizon" theme is being used in UI5 version 1.96.
• The following error is found in the console logs:
  Failed to load resource: the server responded with a status of 404 ()
  /sites?siteId=<SITE_ID>&evictCache=true#Shell-home:1 Access to fetch at 'https://<EXTERNAL_HOST_NAME>/verp/vmod_v1/ui/theming/resources_1.3.49/css/themes/sap_horizon/parameters-bundle.css' from origin 'https://flpnwc-<SUBACCOUNT_HOST>.dispatcher.eu2.hana.ondemand.com' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: The value of the 'Access-Control-Allow-Credentials' header in the response is '' which must be 'true' when the request's credentials mode is 'include'.
  <EXTERNAL_HOST_NAME>/verp/vmod_v1/ui/theming/resources_1.3.49/css/themes/sap_horizon/parameters-bundle.css:1.

• Cloud Portal service on NEO environment

Cloud Portal Service on NEO environment, Cloud, Portal, Service, NEO, UI5, 1.96, 404, sap_horizon,  , KBA , EP-CPP-NEO-FCC-THM , Theme service , Problem