Validity issue

Did you fix this already? That link leads to a confirmation that your page is valid, which is what you want. Is there still a problem?

try the link again? it’s still showing errored for me.

Try changing the <p class="p1"> to <div class="p1"> and see if that helps. Don’t forget to change the closing </p> to </div>.

it worked, thank you.
Is there reasoning behind that?

Well, in a sideways, assbackwards manner. For some reason, paragraph tags and h tags don’t play nicely together with the validator – I haven’t dug around at w3c lately, but there’s probably a reason for that (in XHTML anyway), no doubt something about block level tags etc.

So the first logical thing to do when looking at your source through the validator was to change the p to div since you had another div right nearby that was working.