Mac can be finicky for some people. Here's two ways that had the most success:
Open the app normally, and get the error message you saw. Dismiss the error message, taking care to not let it automatically move the app to the trash.
Right-click on the app, and select 'Open'. You'll get another, slightly different, message, this time with three options. Choose 'Run Anyway'.
If asked, enter your Admin password (and user, if you aren't running as an admin). Note that you may not be asked, depending on a variety of factors.
At this point the app should be running - and you'll be able to quit it, and re-open it normally. This is a one-time-per-application-version process. (So, new versions of the app will require it again.)
OR
- Those who download, do not double click it: right click and extract using a 3rd party extractor like The Unarchiver or Keka
- Double click the extracted app, Mac will show a message saying that it is not allowed to run
- Go to system security settings, unlock it and click to open it
Hope this helped!