You can:
▪ Try another disc to check if the DVD player is dirty or there are bad lens and mainboards.
▪ If a car portable DVD player is not loading discs, check the '''tin ribbon wire''' that connects the optic lens and the mainboard.
▪ Check if the problematic '''disc is dirty or scratched'''. And fix the scratched DVD using toothpaste, peanut butter, Vaseline or copy the scratched DVD into video files.
▪ Check if the DVD is '''region coded,''' otherwise strictly protected, or improperly burned and [https://www.winxdvd.com/resource/best-free-dvd-decrypter-software-review.htm|decrypt the DVD] if necessary.