This journal is (used to be?) published by “ImperialOpen Publishing” and it seems that the whole website https://imperialopen.com/index.php/JPSMS/index is no longer functioning. Suspiciously little can be found about them. I think I found the owner https://www.zoominfo.com/p/Murat-Sarikaya/2645327288
He is present here at RG https://www.researchgate.net/profile/Murat-Sarikaya-2 and one of his projects is called https://www.researchgate.net/project/Journal-of-Production-Systems-and-Manufacturing-Science
Perhaps you can contact him to clarify the matter.