startup problems display after turning on

Hi I'm a new apple user.. Why my Macbook pro 2019 after updating to Catalina always diplays a warning says, it restarted because of a problem and when I reinstalled it, and eventually updated it to newer version of Catalina which is the latest available today.. it shows up again and again every time I open my MacBook. but now when I try to restart it, it takes long time to boot up and any foce startup key commands won't help..