Accreditation is a means of quality assurance within the U.S. American education system. It is granted by private U.S. organizations and ensures that your grade is not a fake.
State universities from other countries usually don’t ask for such an accreditation. They are under permanent quality control by their national Ministries of Education with their countries being members of the international organizations, such as United Nations.
Please find below the confirmation by the Royal Thai Ministry of Education on Ramkhamhaeng University and its international programs. Please feel free to use the contact data mentioned to verify this document.