Hello, 
I am struggling with this issue for some time now and didn't found any solution or help from  anywhere so far. So I've decided to create a ticket here. 
From the beginning, I am trying to extract ValueSets and Measure logic for CMS122v11 from zip files ( https://ecqi.healthit.gov/ep-ec?qt-tabs_ep=1 ). For this purpose, I am using cqm-parser  ( https://github.com/projecttacoma/cqm-parsers ). I am running the script and still getting "Error communicating with VSAC" message. 
Here are my findings. It seems that the problem is directly in the request to VSAC API:

I have chcecked and confirmed that the request URL is correct along with the apikey for authentication. After sending request, I receive response code "0" everytime, which in result give me "Error communicating with VSAC" message. 

I've used generated URL from this cqm-parser in POSTMAN request and i've received correct repsonse code "200" and body with valusets. Based on that i am assuming that something is wrong in sending requests. Path to the file where problem occurs (https://github.com/projecttacoma/cqm-parsers): "lib/util/vsac_api.rb"
How whole request is being build: 

I've also tried to authorize by TGT/ST to VSAC API but i am receiving the same error and same response code "0". 
Maybe some one encountered similar problems, or at least can point me the direction with that. I've noticed that dczulada is one of the authors of cqm-parser. Maybe he could help with this.