The application has encountered an unknown error

I want to test a survey on the demo server. The survey can be accessed via web link:

When I press the ‘Start new Interview’ button I receive the following error (attachment):

The survey has shown no error in the designer after compiling it. Can you please help on this error. Thanks in advance.


Make sure that this assignment is made to a user in the role INTERVIEWER.


One respondent is facing the same issue:

  • We sent a bulk email to respondents (my self included to test)
  • One of the respondents got the following message: "The application has encountered an unknown error :frowning: )
  • I have confirmed that he has the INTERVIEWER role in the server
  • Also checked that I could access other assignments (I could)

This is weird because none of the other respondents had any problem logging in. Thus, we are wondering if there something else to be checked.

Any advice is appreciated :slight_smile:

@andresarau, I am puzzled by:

It is not the respondent, who should have the interviewer account. It is the responsible for the assignment, who must be in the interviewer role (in other words the assignment must be assigned to an interviewer). You don’t have to create interviewer accounts for your respondents to collect CAWI surveys (though it’s possible in principle).

If the above is just weird wording, but you believe the setup is correct, contact the support directly with

  • the server address,
  • assignment number and link, at which the above error was obtained,
  • date/time/ip when the URL was accessed,
  • the browser descriptives.

Since this is an “unknown error” there is nothing that can be said just from this message alone.

PS: make sure this is repetitive, not a temporary unavailability due to e.g. today’s release of v20.01.

Thank you Sergiy,

I assigned a supervisor as the responsible of the assignment. We haven’t encounter any other error so far. I will share the infomration with the support team so they can investigate further.

Many thanks for your quick response

Well, that is exactly the cause of the problem.

Issue solved!!! Thanks!