holch wrote: What I don't understand is why your emails are not sent, because they don't have a valid date, because I have never used the valid date in the tokens either and it is not a problem.

Could be a bug or any other invalid information being imported from CSV file like a wrong "emailstatus" flag.

Which Limesurvey version do you use?

Can you reproduce the problem at our demo which always runs the latest code?