Thank you for your interest in our survey. This time we have already reached the maximum number of participants. However, we look forward to your participation in the next survey.

Why surveys are sometimes closed after a short time...
Usually a very specific number of interviews has to be achieved for a study, sometimes in a very short period of time. The number of people actually responding to an invitation varies from survey to survey. We therefore always have to invite more people than required.
If the number of participants is achieved, the survey closes automatically. Unfortunately, this was the case here. We thank you for your understanding.