I have a number of surveys running at the moment. There is one survey where it gives me an error when I try to enter the data entry screen:

Server error
500
The website encountered an error while retrieving https://URL/limesurvey/index.php/admin/dataentry/sa/view/surveyid/ID. It may be down for maintenance or configured incorrectly.

All of the other surveys running at the moment I can click through to data entry no problems. I have tried giving a different user access to the survey and they can't access data entry either. I have also tried exporting and then importing the whole survey and the new version won't let me data enter. I have tried exporting and importing a completely different survey and that new survey will let me data enter, so it is something specific to that particular survey design. It is a closed access survey (with tokens) but I have other closed access surveys which will let me data enter.
Is there something in the settings that may block the ability to data enter that I have missed?

Hi,

1st : try to activate debug mode : www.limesurvey.org/manual/Debug_mode and return the information provided
2nd: have a look at the server log

Denis

Further to Denis' advice, in your imported test, try removing groups and/or questions to see if the problem is caused by a specific group or question.