diff --git a/packages/volto/news/6515.bugfix b/packages/volto/news/6515.bugfix
new file mode 100644
index 0000000000..c55ab658d9
--- /dev/null
+++ b/packages/volto/news/6515.bugfix
@@ -0,0 +1 @@
+Fixes ICS download in non-public event content. @sneridagh
diff --git a/packages/volto/src/components/theme/EventDetails/EventDetails.jsx b/packages/volto/src/components/theme/EventDetails/EventDetails.jsx
index e1ba3dfb89..bbc7964c77 100644
--- a/packages/volto/src/components/theme/EventDetails/EventDetails.jsx
+++ b/packages/volto/src/components/theme/EventDetails/EventDetails.jsx
@@ -6,7 +6,7 @@ import {
   Recurrence,
 } from '@plone/volto/components/theme/View/EventDatesInfo';
 import Icon from '@plone/volto/components/theme/Icon/Icon';
-import { expandToBackendURL } from '@plone/volto/helpers/Url/Url';
+import { flattenToAppURL } from '@plone/volto/helpers/Url/Url';
 
 import calendarSVG from '@plone/volto/icons/calendar.svg';
 
@@ -147,7 +147,7 @@ const EventDetails = ({ content, display_as = 'aside' }) => {
           className="ics-download"
           target="_blank"
           rel="noreferrer"
-          href={`${expandToBackendURL(content['@id'])}/ics_view`}
+          href={`${flattenToAppURL(content['@id'])}/ics_view`}
         >
           {intl.formatMessage(messages.downloadEvent)}
         </a>
diff --git a/packages/volto/src/components/theme/EventDetails/__snapshots__/EventDetails.test.jsx.snap b/packages/volto/src/components/theme/EventDetails/__snapshots__/EventDetails.test.jsx.snap
index 1d605e546b..a7fad6aa2f 100644
--- a/packages/volto/src/components/theme/EventDetails/__snapshots__/EventDetails.test.jsx.snap
+++ b/packages/volto/src/components/theme/EventDetails/__snapshots__/EventDetails.test.jsx.snap
@@ -127,7 +127,7 @@ exports[`renders event details component with all props 1`] = `
     />
     <a
       className="ics-download"
-      href="http://localhost:8080/Plone/++api++/my-page/ics_view"
+      href="/my-page/ics_view"
       rel="noreferrer"
       target="_blank"
     >
@@ -169,7 +169,7 @@ exports[`renders event details component with only required props 1`] = `
     />
     <a
       className="ics-download"
-      href="http://localhost:8080/Plone/++api++/my-page/ics_view"
+      href="/my-page/ics_view"
       rel="noreferrer"
       target="_blank"
     >
@@ -211,7 +211,7 @@ exports[`renders event details component without links to api in the text 1`] =
     />
     <a
       className="ics-download"
-      href="http://localhost:8080/Plone/++api++/my-page/ics_view"
+      href="/my-page/ics_view"
       rel="noreferrer"
       target="_blank"
     >
diff --git a/packages/volto/src/components/theme/View/__snapshots__/EventView.test.jsx.snap b/packages/volto/src/components/theme/View/__snapshots__/EventView.test.jsx.snap
index acf53acafc..269d255c4b 100644
--- a/packages/volto/src/components/theme/View/__snapshots__/EventView.test.jsx.snap
+++ b/packages/volto/src/components/theme/View/__snapshots__/EventView.test.jsx.snap
@@ -251,7 +251,7 @@ exports[`renders an event view component with all props 1`] = `
           />
           <a
             className="ics-download"
-            href="http://localhost:8080/Plone/++api++/my-page/ics_view"
+            href="/my-page/ics_view"
             rel="noreferrer"
             target="_blank"
           >
@@ -357,7 +357,7 @@ exports[`renders an event view component with only required props 1`] = `
           />
           <a
             className="ics-download"
-            href="http://localhost:8080/Plone/++api++/my-page/ics_view"
+            href="/my-page/ics_view"
             rel="noreferrer"
             target="_blank"
           >
@@ -458,7 +458,7 @@ exports[`renders an event view component without links to api in the text 1`] =
           />
           <a
             className="ics-download"
-            href="http://localhost:8080/Plone/++api++/my-page/ics_view"
+            href="/my-page/ics_view"
             rel="noreferrer"
             target="_blank"
           >
diff --git a/packages/volto/src/express-middleware/files.js b/packages/volto/src/express-middleware/files.js
index 40f3f5d71a..547165f201 100644
--- a/packages/volto/src/express-middleware/files.js
+++ b/packages/volto/src/express-middleware/files.js
@@ -30,7 +30,10 @@ function filesMiddlewareFn(req, res, next) {
 export default function filesMiddleware() {
   const middleware = express.Router();
 
-  middleware.all(['**/@@download/*', '**/@@display-file/*'], filesMiddlewareFn);
+  middleware.all(
+    ['**/@@download/*', '**/@@display-file/*', '**/ics_view'],
+    filesMiddlewareFn,
+  );
   middleware.id = 'filesResourcesProcessor';
   return middleware;
 }