I got this sometimes. It means lots of things. If the survey is still available, try it again later on.
- Target survey is temporary down at the moment
- The survey is unavailable now because of some reason like "Reach enough quota"
- They have enough people working on this survey right now. You can try it again since someone may not qualify, then it will release the quota back to other people.
The new version PL seems fix the problem telling me "the survey is now closed" at the end. However, if the survey itself has different quota counter, then you will still get "the survey is now closed" from the survey itself.