To reproduce this issue, please download and install Klaros-Testmanagement Community Edition from the web site: www.klaros-testmanagement.com/download
Installation Notes can be found here: [https://www.klaros-testmanagement.com/files/doc/html/User-Manual.Installation.html](Installation Notes)
After a successful installation, create a Mantis issue management system entry as described in the Documentation in section: [https://www.klaros-testmanagement.com/files/doc/html/User-Manual.Configure.Main-IntegrationSettings.html#User-Manual.Configure.Main-IntegrationSettings.IssueManagement](Section 10.6.1 Integration / IssueManagement)
The URL should link to the root directory of your Bitnami Mantis Instance and an existing project should be added. The application will contact the SOAP endpoint (/api/soap/mantisconnect.php) when you try to verify the connection (The 'world' icon) after entering credentials to log in to Mantis.
This should trigger the bug reported here, and the system should complain with 'The repository has returned an invalid XML response : Bad envelope tag: head'.
By sniffing on the connection you will notice that the soap envelope is preceded by a element which does not belong here.
If you disable ModPageSpeed in your bitnami instance this issue will go away and you should be able to verify the connection.
Let me know if you need additional information and please feel free to contact us at firstname.lastname@example.org for questions regarding the Klaros-Testmanagement application.