Basic question

without being able to see the site live, giving any answer will be difficult.

please post a live link to illustrate the problem.

https://codex.www.ads-software.com/Forum_Welcome#Include_as_much_information_as_possible

https://www.rdeeipe.net/

Thanks for future help

try to deactivate all plugins to see if that removes the empty space;

if it does, re-activate one plugin at a time and test inbetween to see which one is causing the problem.

you could also try to suppress the empty space by adding this to the custom styles:

#wrapper { overflow: hidden; }