Try these three changes. Let us know what they break.
style.css (line 156)
.main-navigation .nav-menu a, .main-navigation .nav-menu a:visited {
border-right: 1px solid #898989;
color: #515151;
font-size: 16px;
font-weight: bold;
padding: 0 10px;
text-decoration: none;
white-space: nowrap; /* ADD Me */
}
style.css (line 205)
.main-navigation .nav-menu .sub-menu li {
background: rgba(0, 0, 0, 0) url("images/menu-bg-trans.png") repeat scroll 0 0;
border-bottom: 1px solid #898989;
/* padding-right: 130px; /* DELETE Me. */
text-align: left;
width: 100%;
}
style.css (line 218)
.main-navigation .nav-menu .menu-item-21 .sub-menu li,
#dgo-footer .main-navigation .nav-menu .menu-item-21 .sub-menu li {
/* width:200px; /* Unnecessary; DELETE Me. */
}
I’m sorry, Carlos, I do not understand what part of the validator is hard to use. It tells you where to find the errors in plain English.
https://validator.w3.org/nu/?doc=http%3A%2F%2Fthesolarconsultants.com%2F
It would not have solved this particular problem for you, but you still need to clear the errors.