Writer's Block:
Writer's block generally occurs when there was insufficient author preparation before attempting the first draft. If this happens to you, determine if your problem stems from insufficient plot detail, research, poorly sequenced plot scenes, narrow character attributes or background, or inconsistent plot elements. Perhaps a combination of things that brought you to a standstill.
Planning and researching for a novel is a pay me now or pay me later situation. If you try to write without sufficient preparation, it might be necessary to discard dozens of pages because you chose the wrong path early in your writing effort. Time spent developing your plot and characters before you start your draft, minimizes your frustration as you develop your story.
Contrivances:
A contrivance is a scene prop or circumstance inserted by the author too close to the point of action. We've all seen television or movie productions where the camera suddenly focuses on a set of kitchen knives. Suddenly, lights go out and the sound of a window breaking soon follows. If the hero avoids harm by stabbing the intruder, the knives become a contrivance to resolve the danger. Movies and television programs get away with contrivances all the time. In a novel, the reader is not as forgiving. An author might use the knives to resolve the danger, but the knives would be presented casually many pages beforehand to avoid appearing contrived.
Unresolved story thread:
Unless the reader understands that a sequel follows that connects this plot to another novel, the reader needs to have all story threads explained to gain a feeling of closure.