TurboTax Premier 2021 for Mac Will Not Open

I downloaded TurboTax Premier 2021 for Mac last week and worked on a federal return for 2021. Now neither the return nor the application will open -- both look like they are opening, a dialogue box appears for about one second (not long enough to read it), the TurboTax ball jumps in the dock and then stops. 

 

I deleted the application and re-downloaded it. Still does not work.   

 

Using Big Sur v11.6.1. 

 

TurboTax support was closed both times I tried to contact them -- first time it was after hours; second time closed for the Holiday (12/27). 

 

Has anyone experienced this problem? What did you do to correct it? 

 

Thanks in advance.