When you view Categories or Archives page, there is “Archive of … categories” on top. It’s a standard in WordPress theme code and is used to indicate the page.

You can hide the “Archive of… categories” title by following:

1- Go to Appearance – Theme Options
2- Select Extra inputs settings tab
3- On Custom CSS insert this CSS
.pagetitle, .pagetitle-desc {display: none;}
4- Click Save settings

Hide "Archive of Categories"