diff --git a/src/Components/RightSidebar/EnvelopeFilesList.vue b/src/Components/RightSidebar/EnvelopeFilesList.vue
index b2e3e017a6..0264fdca98 100644
--- a/src/Components/RightSidebar/EnvelopeFilesList.vue
+++ b/src/Components/RightSidebar/EnvelopeFilesList.vue
@@ -362,19 +362,20 @@ export default {
 			return url.toString()
 		},
 		openFile(file) {
-			if (window.OCA?.Viewer !== undefined) {
+			const fileUrl = generateUrl('/apps/libresign/p/pdf/{uuid}', { uuid: file.uuid })
+			if (OCA?.Viewer !== undefined) {
 				const fileInfo = {
-					source: generateUrl('/apps/libresign/p/pdf/{uuid}', {
-						uuid: file.uuid,
-					}),
+					source: fileUrl,
 					basename: file.name,
 					mime: 'application/pdf',
 					fileid: file.nodeId,
 				}
-				window.OCA.Viewer.open({
+				OCA.Viewer.open({
 					fileInfo,
 					list: [fileInfo],
 				})
+			} else {
+				window.open(`${fileUrl}?_t=${Date.now()}`)
 			}
 		},
 		isSelected(fileId) {
diff --git a/src/components/validation/EnvelopeValidation.vue b/src/components/validation/EnvelopeValidation.vue
index fdeff07789..d332d58a94 100644
--- a/src/components/validation/EnvelopeValidation.vue
+++ b/src/components/validation/EnvelopeValidation.vue
@@ -247,8 +247,8 @@ export default {
 			return n('libresign', '{progress} of {total} document signed', '{progress} of {total} documents signed', total, { progress, total })
 		},
 		viewFile(file) {
+			const fileUrl = generateUrl('/apps/libresign/p/pdf/{uuid}', { uuid: file.uuid })
 			if (OCA?.Viewer !== undefined) {
-				const fileUrl = generateUrl('/apps/libresign/p/pdf/{uuid}', { uuid: file.uuid })
 				const fileInfo = {
 					source: fileUrl,
 					basename: file.name,
@@ -260,7 +260,6 @@ export default {
 					list: [fileInfo],
 				})
 			} else {
-				const fileUrl = generateUrl('/apps/libresign/p/pdf/{uuid}', { uuid: file.uuid })
 				window.open(`${fileUrl}?_t=${Date.now()}`)
 			}
 		},