Reviewing the Jaspersoft logs, entries like this are found:
2018-08-07 17:01:18,351 ERROR CsrfGuard,https-openssl-nio-x.x.x.x-x-exec-1:44 [x|x] - potential cross-site request forgery (CSRF) attack thwarted (user:<anonymous>, ip:x.x.x.x, method:POST, uri:/x, error:required token is missing from the request)
When using CA PPM integrated with Jaspersoft ,you cannot use both HTTP and HTTPS SSL (Mixed Mode) Handling for PPM.
On the CSA > [server] > Properties > Application > Application Server, check the current value for SSL Handling. If you are using HTTPS access with Jaspersoft, change it to "Support only HTTPS".
Also make sure that the HTTPS Entry URL for the app server matches the one you enter in the browser to access PPM.
Restart app services after making those changes.