Hi
1] Check if you can access "Project Site Provisioning Settings". If yes, Please set the site collection here.
2] In case if you are getting errors when accessing "Project Site Provisioning Settings", then run the below query on the publish database and check what value is present. 1 means create project site. 0 means do not create project sites.
select WADMIN_AUTO_CREATE_SUBWEBS from msp_web_admin