Back-end modifications won’t show up on front-end

For some reason WordPress stopped showing the modifications I do in the back-end on the front-end. Especially concerning the widgets.

I’ve been switching widgets and themes but anytime I refresh my website, the adjustments I did aren’t there. If I add or remove a widget from the themes’ sidebars the action seems to have no effect on the website, even after refreshing.

The problem came up after testing HTML codes on Text widget using the Vigilance 1.48 and its child theme My_Vigilance. I don’t know if the things are related; anyway, I deleted all my themes and re-uploaded them but the bug is still there.

I’m not a code-savvy user so I did not mess up with any WP or theme code that I’m aware of.

My website is still in development so I need to be able to continue testings ASAP.

Thanks in advance.

P.S

The widgets appear to work on pages and posts, they do not appear on the homepage where is the theme default sidebar that shows up.