OpenClinica User Manual/content encoding error

= Content Encoding Error =

Introduction
In some not so very rare occasions, OpenClinica-users can login to OpenClinica, add Subjects and some more activities, but when they try to start entering data, an error-message appears, that looks like:

Content Encoding Error (content_encoding_error)

Server response could not be decoded using encoding type returned by server. This is typically caused by a Web Site presenting a content encoding header of one type, and then encoding the data differently.

Cause
OpenClinica itself is not setup to use compression, but tomcat and/or Apache/IIS can be setup to do this. (See for an example this page) If you have not enabled compression then the problem could be in the firewall of your users. Especially TMG, Microsoft's Threat Management Gateway, tries to compress content in order to enhance the performance of InternetExplorer-users. However, this does not work in combination with OpenClinica.

Solution: firewall-side
The best way to solve this is editing the settings of the firewall. Instructions on how to do this if your OpenClinica is behind an ISA firewall, which is the predecessor of TMG, can be found here. But the situation where the user is behind ISA/TMG is not yet described. However not all IT-departments of hospitals are willing to change their security policy.

Solution: client-side
If the firewall settings can not be changed, you can disable this compression by clicking in InternetExplorer: tools, internet options, advanced and then scrolling down to HTTP and unchecking the box with Use HTTP 1.1 through proxy connections