Looking at DV Im getting:
5121 3.046644 5164 Meli_nt.exe [st] [netTalk][thread=2] MatchSubjectWithURL [api.mercadolibre.com] =?= [api.mercadolibre.com]
5122 3.047657 5164 Meli_nt.exe [st] [netTalk][thread=2] Certificate Verified: api.mercadolibre.com = api.mercadolibre.com
5123 3.265226 5164 Meli_nt.exe [st] [netTalk][thread=2] NetSimple.ErrorTrap 0 Error connecting to Service. Server Response: 400 HTTP/1.1 400 Bad Request
5124 3.265226 5164 Meli_nt.exe Content-Type: application/json;charset=UTF-8
5125 3.265226 5164 Meli_nt.exe Transfer-Encoding: chunked
5126 3.265226 5164 Meli_nt.exe Connection: keep-alive
5127 3.265226 5164 Meli_nt.exe Date: Mon, 31 Dec 2018 16:34:12 GMT
5128 3.265226 5164 Meli_nt.exe Vary: Accept,Accept-Encoding
5129 3.265226 5164 Meli_nt.exe Cache-Control: max-age=0
5130 3.265226 5164 Meli_nt.exe X-Content-Type-Options: nosniff
5131 3.265226 5164 Meli_nt.exe X-Request-Id: 6a169c14-c524-4151-9374-f70065cbc5f3
5132 3.265226 5164 Meli_nt.exe X-Frame-Options: DENY
5133 3.265226 5164 Meli_nt.exe X-XSS-Protection: 1; mode=block
5134 3.265226 5164 Meli_nt.exe Access-Control-Allow-Origin: *
5135 3.265226 5164 Meli_nt.exe Access-Control-Allow-Headers: Content-Type
5136 3.265226 5164 Meli_nt.exe Access-Control-Allow-Methods: PUT, GET, POST, DELETE, OPTIONS
5137 3.265226 5164 Meli_nt.exe Access-Control-Max-Age: 86400
5138 3.265226 5164 Meli_nt.exe Strict-Transport-Security: max-age=15724800
5139 3.265226 5164 Meli_nt.exe X-Cache: Error from cloudfront
5140 3.265226 5164 Meli_nt.exe Via: 1.1 92f892199bcce7a13a5283e1376fa0e8.cloudfront.net (CloudFront)
5141 3.265226 5164 Meli_nt.exe X-Amz-Cf-Id: hHhmUxB0iyTHUon-YEU7oQWDU7aBRV7n2rWXa_TWbgcLniUCC2-GVw==
5142 3.265226 5164 Meli_nt.exe
5143 3.265226 5164 Meli_nt.exe {"message":"Wrong number of parameters","error":"invalid_request","status":400,"cause":[]} NetOAuth.PageReceived
See the last line...