Grey line on HomePage & Mobile site non-AMP separate page with errors

Hello. On bet3.GR (https://www.bet3.gr/), there is a grey horizontal line that has been created. I can assume that this happened through tagDiv Composer options. I might have selected something that I had not realized its function.
However, I am currently trying to fix it up, but I cannot discriminate if it is on row, on column or on element options.
There is no way to mark this grrey line via tagDiv Composer Homepage function, so as to change options, make some tests and resolve the issue. Since I cannot send you screenshots, you may open the homepage https://www.bet3.gr/, and carefully watch after horizontal main menu on first row initial modules: text block ΣΤΗΡΙΓΜΑ ΤΗΣ ΗΜΕΡΑΣ on the left, Call-To-Action Ψάχνεις στοιχηματική εταιρεία ΔΟΚΙΜΑΣΕ.

P.S.: There is a second separate issue: I have also created a mobile page for my website (https://www.bet3.gr/) via tagDiv composer, for non-AMP display. But I also edited it by WPBakery on WordPress pages section to customize some text blocks further more and as a result, it now only shows code inside both the page edit environment (classic mode, WPBakery Backend editor) and via tagDiv Composer. Here is my question: Can I delete this mobile site page and create it via tagDiv Composer from the beginning? It is now an entry of mobile page on my declared HomePage on Settings -> Reading.