diff --git a/guix/build/download.scm b/guix/build/download.scm
index db0a39084b..2eee984b31 100644
--- a/guix/build/download.scm
+++ b/guix/build/download.scm
@@ -409,18 +409,24 @@ (define addresses
                  (socket (addrinfo:fam ai) SOCK_STREAM IPPROTO_IP))))
       (catch 'system-error
         (lambda ()
-          (connect* s (addrinfo:addr ai) timeout)
-
+          (pk 'uri (uri->string uri))
+          (pk 'before s (addrinfo:addr ai) timeout)
+          (pk 'connect* (connect* s (addrinfo:addr ai) timeout))
+          (pk 'done)
           ;; Buffer input and output on this port.
           (setvbuf s 'block)
           ;; If we're using a proxy, make a note of that.
           (when http-proxy (set-http-proxy-port?! s #t))
           s)
         (lambda args
+          (pk 'failed s)
           ;; Connection failed, so try one of the other addresses.
           (close s)
+          (pk 'closed)
           (if (null? (cdr addresses))
-              (apply throw args)
+              (begin
+                (pk 'boum)
+                (apply throw args))
               (loop (cdr addresses))))))))
 
 (define (setup-http-tunnel port uri)
@@ -465,6 +471,7 @@ (define https-proxy (let ((proxy (getenv "https_proxy")))
                          (parameterize ((current-http-proxy https-proxy))
                            (thunk))
                          (thunk)))))))
+
     (with-https-proxy
      (let ((s (open-socket-for-uri uri #:timeout timeout)))
        ;; Buffer input and output on this port.