MSXML2.XMLHTTP , Method 'open' of object 'IServerXMLHTTPRequest2' failed

Question

 Dim objHTTPRequest As MSXML2.XMLHTTP
 Set objHTTPRequest = New MSXML2.XMLHTTP

 With objHTTPRequest
    .Open MethodName, strRequest, Asynchronous, strUserName, mstrPassword
    '___________more code here___________
 End with

I am trying to create a serverConnection object by getting the input parameters from the user using a visual basic form. When run the code, I am getting the following error when executing the above code part. I am working on a word add-in and this error is only occurring when I run the code through vb and the created .dll for the product is working properly with Word.

The following error occurred while submitting this request to a server: Method 'open' of object 'IServerXMLHTTPRequest2' failed The server address() may be incorrect

in here,

strRequest= "/api/a1/Properties"

If anybody could, Please tell me why is this happening. Because of that error, I am unable to debug the code for further modifications.