Update README.md

README.md

@@ -130,6 +130,8 @@ On macOS Catalina a warning will be displayed on first install. The app won't op
 
 There is a known issue which prevents the app from starting on some Linux distributions: #231
 
+If after downloading it, you can't execute the file directly, try running `chmod u+x ./jitsi-meet-x86_64.AppImage.AppImage`
+
 The workaround for now is to launch the app like so: `./jitsi-meet-x86_64.AppImage --no-sandbox`
 
 <details><summary>NOTE for old GNU/Linux distributions</summary>