I'm trying to integrate a quiz/survey plugin with an existing Wordpress site. Everything is working well, except that if the user lets a quiz/survey sit idle for awhile (30 minutes is long enough to trigger it) they will be greeted with the following error message when trying to submit their reply:
PHP Sessions error. Check your sessions settings.
I had the same issue,
I fixed it by making sure
/var/lib/php/session folder was set
0777 for permissions, deleted all the session files and did a graceful restart of the server.
Sessions messages went away and voting worked.