When attempting to install a page as an application in Ulaa on Mac by going to the hamburger menu in the top-right corner > Cast, Save and Share > "Install page as app", you may encounter the following error message: “<appname>” is damaged and can’t be opened. You should move it to the Bin" , as shown in the screenshot below:

If an app (like a web app installed from Ulaa) isn’t properly signed and approved by Apple, macOS might show a warning saying it is damaged or unsafe, even if the app is actually fine and safe.
To resolve this issue, follow the steps below to allow the security permission on your Mac :
1. After installing the site or page as an app by going to the hamburger menu in the top-right corner > Cast, Save and Share > "Install page as app",
2. Open System Settings on your Mac > Privacy & Security
3. Scroll to the Security section, and click "Open Anyway" as shown in the screenshot below.