A malformed protocol request was received by the AD FS Web Agent. A sign-in request was received when a response was expected. ...

A malformed protocol request was received by the AD FS Web Agent. A sign-in request was received when a response was expected. 

This request will be failed. 

This situation can occur if other components mistake this server for the Federation Service. 

User Action 
If you are using non-Microsoft federation software in your environment, verify that it is compatible with Active Directory Federation Services (AD FS). 

Ensure that the Uniform Resource Locator (URL) for this application is not configured as the Federation Service URL at any Web agent, Federation Service Proxy, or resource partner.