New trunk seal, now I can't close the trunk

Just because you removed a seal that looked like the one you put on doesn't make it right. Could have been replaced incorrectly any time along it's 40+ year life.
Sofseal was the mfg that I had problems with the first time, then I bough then next cheap one....Metro. Just the wrong material and too thick.

If they fail you, just bite the bullet and your problems will be solved. Steele Rubber Co.