Did you cook the noodles?
If the noodles are raw, at least an hour, if not raw, just until heated through...about 40 minutes....use an instant read in the center of the dish to check...should be about 180.
I cook it covered for the first half of the time then remove the cover.
And be sure to let it sit for at least 15 minutes before you cut it....lets the juices even out.
Linda C

Thanks Linda. The noodles were boiled.
I haven't had lasagna for so long. I'm really looking forward to this.

What Linda C said - at 375

I agree, about 40-45 minutes at 375. I remove the foil for the last 20 minutes or so too, because I like the cheese to get a little crispy and browned on the top.

Be sure to check the middle, if it's refrigerated you'll need enough time to heat it through.

Annie