HTTP Error 411. The request must be chunked or have a content length in VSTS web test 2017

Problem: 

I recorded a web test and while playing back , one of my request is failing with error :

HTTP Error 411. The request must be chunked or have a content length.  when I try to replay this request with same data in fiddler or postman, request is returning status code 200. 

Analysis

• I verified headers  , query string parameters in the request but I don't see any difference. 
• When i verify in App insights, I don't see this request in app insights. 

Solution : 

• Create a new request 
• right click on next request and click on insert new request . 
• copy URL from failing request 
• Copy query string parameters and headers from failed request. 
• delete failed request . 
• Execute web test .. request is successful with http status code - 200.  

Request failed: Exception occurred: Could not load file or assembly

Problem: 

When we add any web test plug in or web request plug in we are getting  error “Request failed: Exception occurred: Could not load file or assembly '<<Solution name>>, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified.” 

Solution : We have to add your .CS file or folder contains file in deployment directory. 

Solution items --> Local.test settings --> Deployment --> Enable deployment (check box) and then add file / directory --> Save test settings.