Enable HTTP using Telnet for HP 1920G Switch

Dear all,

I have an  HP 1920G Switch. 

I enabled only the service telnet and HTTPS.

I could not access the switch using HTTPS, but I could access the switch using telnet but I do not know what is the command to enable HTTP, and to check what I did not configure regarding HTTPS. I am getting an error certificate error when I try to access the switch using HTTPS. 

Thanks a lot.