1. The journal imposes a “submission fee” or just pays for submission. In fact, after submission, it is not certain that it will be published. Open journal-based journals (such as INKLUSI) generally live from author contributions, but the fee requested is usually for a “publication fee”, aka publishing costs.
2. The Editorial Board is suspicious. The number may be too small or the names are hard to track. If you are an expert in that field, of course you know who the experts are in your field. You don’t know these people.
3. A publication has many journals. Publisher A, for example, publishes dozens of journals that are not even related to each other in terms of their fields.
4. The journal states that it will publish an issue of so and so in the future, but it never appears.
5. The website appearance is mediocre, looks unprofessional.
6. The journal is called an “international journal of …” or “national journal of ,,,” but the editorial board does not reflect its name.
7. There are many errors in the title and abstract (let alone the content). These errors can be grammatical errors, typos, or even substance. The content of the journal does not match its scope. It says it is a social work journal, but the content is mathematics education. Or, the articles are a mix of various disciplines that are not as specific as the journal name.
source: https://ejournal.unsrat.ac.id/v2/index.php/jab/announcement/view/23