Here Are the Main Reasons!
A lot of people assume their resume was rejected by an ATS simply because they were not qualified enough. Sometimes, though, the problem is the way the resume is structured. Applicant tracking systems are designed to scan resumes and identify information such as job titles, skills, experience, education, and keywords that match the position. If a resume is filled with complicated layouts, graphics, unusual columns, images, or text placed inside elements that the system cannot read properly, important information may not be recognized. Using a completely different job title from the one mentioned in the vacancy can also make it harder for the system to identify a relevant match.
That does not mean you should fill your resume with keywords just to beat the system. If the document is stuffed with unrelated terms, it may look unnatural when a recruiter reads it. I think the better approach is to create a clean, simple resume and describe your actual experience using terminology that genuinely matches the job description. Make your skills specific and explain what you actually did rather than simply listing generic abilities. Before submitting, check whether the file can be read normally when converted to plain text and make sure your most important information is easy to find. An ATS-friendly resume should ultimately be easy for both software and humans to understand.