Accounting module installation take more time so now so we  have to  increase timeout of nginx server. Please check and if not work then you should install accounting with starting http://IP:8069/. Please note that we are using 8069 port. Hope this help.

Same issue discussed on community: https://www.odoo.com/groups/community-59/community-12858965?mode=thread&date_begin=&date_end=