In my case, I have received rejection after seven months from submission to journal without reason or editor comments (decline). Moreover, without being reviewed by an expert scientist reviewer, any suggestions?
Dear Abdalrhman Milad renowned journal normally do not only have an editor-in chief but also co-editors and advisors. Often they do an editorial screening of incoming manuscripts and which of them will be sent out for peer-review. Those manuscripts that are not sent to reviewers are "desk-rejected" by the editor. This means that they are sent back to the authors without any reviewers comments. It appears this happened to your manuscript. Reasons for desk-rejection can be different. Occasionally the topic of the work described in a manuscript does not match the scope of the journal. Common reasons for desk-rejection are "lack of novelty" or "not of sufficient interest to the broad readership of the journal". This could mean that the research is either somewhat routine or too specialized for the journal. For more information please see the following link entitled "5 likely reasons why your paper was (desk-)rejected":
This seems to be two questions - Why was your article rejected? and Why did they not give you any reason for the rejection?
Editors which have a peer review process will usually summarize what the reviewers said about your article and send it to you. Generally, the answers are yes for publication without changes (rare), yes with changes, or no for a reason. That reason could be they have a similar article in the pipeline, the subject matter doesn't fit well with the journal or the quality they require isn't there. Keep in mind, rejection is common in the publishing business.
You don't say if you sent the journal a query letter asking about their interest in the topic ahead of time. The common protocol is you can send a query letter to as many journal editors as you want but the manuscript to only one journal at a time. It is definitely to your advantage to query before sending a manuscript because it can take months before your manuscript will be reviewed. With a query letter, the response is generally faster or not at all. If they don't respond, consider the answer a no. If you want, you can see my course on writing for publication. It's free to view and designed mostly for nurses but the process is generally the same for most disciplines. Good luck! https://www.rnceus.com/course_frame.asp?exam_id=114&directory=publishing
Dear Abdalrhman Milad renowned journal normally do not only have an editor-in chief but also co-editors and advisors. Often they do an editorial screening of incoming manuscripts and which of them will be sent out for peer-review. Those manuscripts that are not sent to reviewers are "desk-rejected" by the editor. This means that they are sent back to the authors without any reviewers comments. It appears this happened to your manuscript. Reasons for desk-rejection can be different. Occasionally the topic of the work described in a manuscript does not match the scope of the journal. Common reasons for desk-rejection are "lack of novelty" or "not of sufficient interest to the broad readership of the journal". This could mean that the research is either somewhat routine or too specialized for the journal. For more information please see the following link entitled "5 likely reasons why your paper was (desk-)rejected":