Simple answers to complex questions.

I didn't have such a glitch! Check if all other tasks are completed, for example, collecting 1000 skeletons! If you can't find it, look for the mission Walkthrough on this same forum! There is a separate thread for each mission! See if you can find the answer there!

Some people don't have such glitches, my friends didn't either, but it happened to me; meanwhile, in the game I completed all missions and tasks, gathered 20 dragons, but that damn portal still wouldn't let me through!!! I thought maybe there was a typo by the authors and decided to gather 200 dragons (both times I also tried to pass with spectral dragons) but even then the evil portal didn't let me in.... since I completed everything and gathered a huge army, I entered the mission victory code with a clear conscience