VERIFIED SOLUTION i

Resolving Portrait Dialogue Questionnaire login redirect error: Answer Form Object referred in ViewState not found in Session cache


 

Issue

Two web servers in the load balancers are synchronised using machine key.
Validation key and decryption key were set for config file in IIS.

Questionnaire that is served using a shortened URL sometimes work, other times there is a repeated loop of logins then they are opened. This behaviour is also observed for not shortened URL.

Running the questionnaire on e.g. smartphone results in too many redirects error.
User-added image


Logs shows: BaseException message: Answer Form Object referred in ViewState not found in Session cache.

The issue was observed when an environment was upgraded to Portrait Dialogue 6.1.
 

Cause

The session gets lost from no apparent reasons. In the past these issues have never been experienced and conventional way of synchronizing machine keys had always did their work.

Resolution

UPDATED: September 5, 2017
Now it is necessary to use sticky sessions or out of process session state in ASP.NET.
This behaviour presented above was stopped when sticky-session was set up.