diff --git a/guix/http-client.scm b/guix/http-client.scm
index a2e11a1b73..51bba250d5 100644
--- a/guix/http-client.scm
+++ b/guix/http-client.scm
@@ -38,7 +38,7 @@
   #:use-module (guix utils)
   #:use-module (guix base64)
   #:autoload   (gcrypt hash) (sha256)
-  #:autoload   (gnutls) (error/invalid-session)
+  #:autoload   (gnutls) (error/invalid-session error/again)
   #:use-module ((guix build utils)
                 #:select (mkdir-p dump-port))
   #:use-module ((guix build download)
@@ -163,7 +163,8 @@ reusing stale cached connections."
       (if (or (and (eq? key 'system-error)
                    (= EPIPE (system-error-errno `(,key ,@args))))
               (and (eq? key 'gnutls-error)
-                   (eq? (first args) error/invalid-session))
+                   (memq (first args)
+                         (list error/again error/invalid-session)))
               (memq key
                     '(bad-response bad-header bad-header-component)))
           #f
diff --git a/guix/scripts/substitute.scm b/guix/scripts/substitute.scm
index 48309f9b3a..65940591a9 100755
--- a/guix/scripts/substitute.scm
+++ b/guix/scripts/substitute.scm
@@ -45,7 +45,7 @@
                 #:select (uri-abbreviation nar-uri-abbreviation
                           (open-connection-for-uri
                            . guix:open-connection-for-uri)))
-  #:autoload   (gnutls) (error/invalid-session)
+  #:autoload   (gnutls) (error/invalid-session error/again)
   #:use-module (guix progress)
   #:use-module ((guix build syscalls)
                 #:select (set-thread-name))
@@ -417,7 +417,8 @@ server certificates."
         (if (or (and (eq? key 'system-error)
                      (= EPIPE (system-error-errno `(,key ,@args))))
                 (and (eq? key 'gnutls-error)
-                     (eq? (first args) error/invalid-session))
+                     (memq (first args)
+                           (list error/again error/invalid-session)))
                 (memq key '(bad-response bad-header bad-header-component)))
             (proc (open-connection-for-uri/cached uri
                                                   #:verify-certificate? #f