diff --git a/src/frontend/app/viewer/document-viewer.component.ts b/src/frontend/app/viewer/document-viewer.component.ts
index e6ae0474073f4bdf4f0c1d878469523162b7b36f..afc7ff1895a392c8604cfd74cfced07df9147ef0 100644
--- a/src/frontend/app/viewer/document-viewer.component.ts
+++ b/src/frontend/app/viewer/document-viewer.component.ts
@@ -397,7 +397,7 @@ export class DocumentViewerComponent implements OnInit {
     }
 
     canBeConverted(file: any): boolean {
-        const fileExtension = '.' + file.name.split('.').pop();
+        const fileExtension = '.' + file.name.toLowerCase().split('.').pop();
         if (this.allowedExtensions.filter(ext => ext.canConvert === true && ext.mimeType === file.type && ext.extension === fileExtension).length > 0) {
             return true;
         } else {
@@ -406,7 +406,7 @@ export class DocumentViewerComponent implements OnInit {
     }
 
     isExtensionAllowed(file: any) {
-        const fileExtension = '.' + file.name.split('.').pop();
+        const fileExtension = '.' + file.name.toLowerCase().split('.').pop();
         if (this.allowedExtensions.filter(ext => ext.mimeType === file.type && ext.extension === fileExtension).length === 0) {
             this.dialog.open(AlertComponent, { autoFocus: false, disableClose: true, data: { title: this.lang.notAllowedExtension + ' !', msg: this.lang.file + ' : <b>' + file.name + '</b>, ' + this.lang.type + ' : <b>' + file.type + '</b><br/><br/><u>' + this.lang.allowedExtensions + '</u> : <br/>' + this.allowedExtensions.map(ext => ext.extension).filter((elem: any, index: any, self: any) => index === self.indexOf(elem)).join(', ') } });
             return false;