Thank you Thaddy.
Based on the link you presented, operating systems like Windows 10, Window Server 2019, Windows 11, etc. must be using TLS1.2. Aren't they?
I found the reason. I opened a browser at the same machine as web server (Window Server 2019), and it displayed the error.
Cannot create file 'c:\windows\temp\CGI00000.tmp',
which file already existed.
I deleted the CGI*****.tmp files and tried, and everything works fine. The numbers are added by 1 every time.
Probably my re-starting of the server may have caused this problem, resetting the file index number to zero.