HELP with W3C Validator Options

[temeter]

Hello.

A friend of mine have a website and we want to check it and validating for errors (WCAG 2.0 AA). So, when I check it in https://validator.w3.org I got some errors like above:

ERROR1: ------------Element head is missing a required instance of child element title.----------

From line 1, column 736; to line 1, column 742

d/atom/"/></head><

Content model for element head:
If the document is an iframe srcdoc document or if title information is available from a higher-level protocol: Zero or more elements of metadata content, of which no more than one is a title element and no more than one is a base element.
Otherwise: One or more elements of metadata content, of which exactly one is a title element and no more than one is a base element.



ERROR2: ------------link element between head and body.-------------

From line 1, column 743; to line 1, column 914

"/></head><link type="text/css" media="all" href="https://www.yourphysiopath.gr/wp-content/cache/autoptimize/css/autoptimize_365c6b81cd9cf8d3a27dc3e25a4b9a5e.css" rel="stylesheet" /><link


ERROR3: ------------Cannot recover after last error. Any further errors will be ignored.----------------

From line 1, column 743; to line 1, column 914

"/></head><link type="text/css" media="all" href="https://www.yourphysiopath.gr/wp-content/cache/autoptimize/css/autoptimize_365c6b81cd9cf8d3a27dc3e25a4b9a5e.css" rel="stylesheet" /><link



The website is Wordpress site. I have tried several plugins to fix them and some edit in header.php but I can't find anything else. Where I can find those html codes to fix them? In which wordpress file/s? Can you help please?

Thank you.

[temeter]

No problem. Even what you did and give some help is very important

Thanks.