Unexpected HTML code being displayed on all pages at the top left corner

[sliknat]

For a few months now there is HTML code being displayed in the top left corner of our website (all pages). I have done some research, contacted Shopify and also the third party for the themes app. But no one has yet been able to provide a solution. This is why I am now seeking help here. Perhaps someone has experienced similar issues.

I have attached screenshots.

Any help is very much appreciated. 

Thanks in advance.

[DelightCart]

@sliknat Can you please send me store url?

[sliknat]

Yes, of course. It is https://slikstative.com/.