Dear sir,
Please go to file: \templates\sj_stabwall\index.php and remove this code:
<div class="ip-loader">
<svg class="ip-inner" width="60px" height="60px" viewBox="0 0 80 80">
<path class="ip-loader-circlebg" d="M40,10C57.351,10,71,23.649,71,40.5S57.351,71,40.5,71 S10,57.351,10,40.5S23.649,10,40.5,10z"/>
<path id="ip-loader-circle" class="ip-loader-circle" d="M40,10C57.351,10,71,23.649,71,40.5S57.351,71,40.5,71 S10,57.351,10,40.5S23.649,10,40.5,10z"/>
</svg>
</div>

Thanks.

Not working. When removing that code the page is in blank. No solution yet?

Dear sir,
Please submit ticket and send us your information to check this issue

Thanks.

it not be removed
just replace it
Templates - SJ Stabwall - General - Logo - Logo Loadding
You can replace it with clear 1x1px png,

One more issue:
If you dont work with LESS, you can add this code in to yor CSS style file- templates\sj_stabwall\css\template-{your color}.css :

opacity: 0;

in to .ip-header block (strings 1813 - 1820)

If you work with LESS sdd this code in to your color style less file in the LESS derictory:

.ip-header {
opacity: 0;
}