Unable to open My Heritage Family Tree Builder application post download

Hi, I am unable to keep the Family Tree Building application open. It flashes up with the menu at top of screen then nothing. I have been working with My Heritage for many weeks with no progress. I have uninstalled, reinstalled, shut down and nothing.

Last question from My Heritage was what anti virus was I using? I don't as I believe Mac has this built in? I have never had a problem downloading an application and using.

My iMac (late 2015 model) is currently using Monterey version 12.6.5.

Has anyone else had this issue and found a resolution? Many thanks in advance.