Thanks! I did that. I have 342 errors and 17 warnings!! A long list. BUT I don't know what to do next! I am NOT technically minded. It just says "fix them"... HOW?? Can I just check the box that says "validate error pages" or "clean up" or....??
The notes say: The following notes and warnings highlight missing or conflicting information which caused the validator to perform some guesswork prior to validation, or other things affecting the output below. If the guess or fallback is incorrect, it could make validation results entirely incoherent. It is highly recommended to check these potential issues, and, if necessary, fix them and re-validate the document.
The validator checked your document with an experimental feature: HTML5 Conformance Checker. This feature has been made available for your convenience, but be aware that it may be unreliable, or not perfectly up to date with the latest development of some cutting-edge technologies. If you find any issues with this feature, please report them. Thank you.