Catalina 10.15.5 update error (-42023)

I am trying to update my Mac Air to the latest Catalina 10.15.5 version. Once I click 'update' it appears to go through the update process for about a minute before it then brings me back to the regular computer log-in page. I enter my password and log in and then an error message saying "An unknown error occurred (-42023)." This keeps happening and the computer won't update. Please help!!