if you are using cpanel then it won't redirect to HTTPS automaticly, it's just how cpanel is. Chevereto has never detected HTTPS with cpanel. So i have to use code from server issues page to make script use https. Otherwise it won't, but if you use plesk you can setup so server shall redirect visitors directly to https automaticly.
Otherwise you can setup permantent redirect method in cpanel from http:// to https://
actually it is a cpanel thing, since i have used default settings like over 10 times and chevereto has never used https automaticly, it keeps staying in http. So some configuration seems to be needed. But it does work on other scripts that has auto detect then they use https. Only chevereto won't with default settings of cpanel installation.