Paper getting rejected from many journals after no proper review - What could be the problem? It has been approximately 2 years that we are trying to a push a paper(CS) to get it published. We think, the work is/was a novel that focused on the development of a new dynamic system that works under uncertainty constraints. However, it gets rejected every time and the most frustrating thing is that the reviews we get are completely absurd. Please see the following reasons of rejection in brief (Duration of review is written in bracket). Submission to subsequent journals also included after incorporating review comments of the previous journal.

Journal 1: The abstract should not contain citation. [14 months]
Journal 2: The paper is out of scope.[2.5 months] -- The paper was actually coming in the scope of the journal. But, after request also, the EIC didn't take it.
Journal 3: This journal have stopped publishing papers related to ... [1 month]
Journal 4: Similar type of work was done in [some old papers published by journals in Beall's list]. Hence, it does not offer any novelty. [7 months] -- We are sure that the reviewer didn't read the paper. Probably, (she)he did some google search over the title. Got something and commented.

After lots of improvement and getting the paper reviewed by few fellow researchers in our lab, we are not getting anything substantial about such random rejection.

What could be some possible problem?
Should we put the paper in the garbage and move on with other works?
Are these predatory publishers (published articles) the rejection for our paper?
I don't think there is only one reason for all the rejections you got. The first journal seemed to reject you because of a formality, which could have been prevented (abstracts usually never have citations). Maybe they think if you can't follow the submission guidelines to every last bit you don't deserve to be published (which can be unreasonable).

After that your research was already 14 months old. Did you do a new literature research? The novelty could have faded during that time. Journal 2's and 3's rejections seem legit and happened in a relatively reasonable time frame.

I guess journal 4's answer does look like the editor/referee didn't read it in detail. But before accusing them of lack of interest or ethics, you should ask yourself if your research has the quality and novelty to be published. 

You also need to overthink your choice of journals. High-impact journals are often not the best choice for your research due to their high standards. They also tend to not publish very specialized articles.

My concrete advice: Review your article and try to improve it. Get criticism from colleagues and take it seriously. Compare your article to similar articles from your field and apply those same standards. Then choose a journal that is common in your field and that published articles related to your work and try there. Good luck!