What are the possible reasons for the rejection of the paper?

There are many reasons why papers are rejected. Here are some common reasons:

-the quality of the paper is not high enough, including insufficient experimental data, insufficient analysis and unclear conclusions.

-the paper lacks innovation and does not put forward new ideas or methods.

-the paper does not conform to the theme or scope of the journal, or does not conform to the readers of the journal.

-There are grammatical errors, spelling errors and formatting errors in the paper.

-there is plagiarism or plagiarism in the paper.