Prestashop nginx redirects on PLESK

Have a multistore prestashop, running on Plesk Onyx nginx. Since moving to the new server, there are all sorts of redirect errors. Most of them give the white nginx gateway error page, not the correct errordocument. Some links work only with NO trailing slash, some only WITH it, particularly if the language id )like /en/ is present in the url, or parameters in the url. There is the location detection module which sets the correct language and currency according to the visitor's IP and once done it redirects to '[login to view URL]', resulting an error. Also according to pingdom tools, there are too ,any redirects, back and forth from http and https: [login to view URL] -> [login to view URL] -> [login to view URL] -> [login to view URL] -> [login to view URL] And sometimes it gives a gateway error for no reason for a decent url, clearing cookies or switching to another browser gives no errors. You need to know both the prestashop and nginx (or apache, can switch to apache if necessary).