diff --git a/lib/pleroma/web/activity_pub/mrf.ex b/lib/pleroma/web/activity_pub/mrf.ex
index 5e5361082..28473a134 100644
--- a/lib/pleroma/web/activity_pub/mrf.ex
+++ b/lib/pleroma/web/activity_pub/mrf.ex
@@ -51,6 +51,11 @@ defmodule Pleroma.Web.ActivityPub.MRF do
     Enum.any?(domains, fn domain -> Regex.match?(domain, host) end)
   end
 
+  @spec instance_list_from_tuples([{String.t(), String.t()}]) :: [String.t()]
+  def instance_list_from_tuples(list) do
+    Enum.map(list, fn {instance, _} -> instance end)
+  end
+
   @callback describe() :: {:ok | :error, Map.t()}
 
   def describe(policies) do
diff --git a/lib/pleroma/web/activity_pub/mrf/simple_policy.ex b/lib/pleroma/web/activity_pub/mrf/simple_policy.ex
index 22cb242fc..48463f996 100644
--- a/lib/pleroma/web/activity_pub/mrf/simple_policy.ex
+++ b/lib/pleroma/web/activity_pub/mrf/simple_policy.ex
@@ -183,9 +183,7 @@ defmodule Pleroma.Web.ActivityPub.MRF.SimplePolicy do
 
   defp instance_list(config_key) do
     Config.get([:mrf_simple, config_key])
-    |> Enum.map(fn
-      {instance, _} -> instance
-    end)
+    |> MRF.instance_list_from_tuples()
   end
 
   @impl true
diff --git a/lib/pleroma/web/activity_pub/publisher.ex b/lib/pleroma/web/activity_pub/publisher.ex
index 9c3956683..e4e9cfb69 100644
--- a/lib/pleroma/web/activity_pub/publisher.ex
+++ b/lib/pleroma/web/activity_pub/publisher.ex
@@ -126,6 +126,7 @@ defmodule Pleroma.Web.ActivityPub.Publisher do
 
       quarantined_instances =
         Config.get([:instance, :quarantined_instances], [])
+        |> Pleroma.Web.ActivityPub.MRF.instance_list_from_tuples()
         |> Pleroma.Web.ActivityPub.MRF.subdomains_regex()
 
       !Pleroma.Web.ActivityPub.MRF.subdomain_match?(quarantined_instances, host)
diff --git a/test/web/activity_pub/mrf/mrf_test.exs b/test/web/activity_pub/mrf/mrf_test.exs
index e82c8afa6..042590926 100644
--- a/test/web/activity_pub/mrf/mrf_test.exs
+++ b/test/web/activity_pub/mrf/mrf_test.exs
@@ -59,6 +59,15 @@ defmodule Pleroma.Web.ActivityPub.MRFTest do
     end
   end
 
+  describe "instance_list_from_tuples/1" do
+    test "returns a list of instances from a list of {instance, reason} tuples" do
+      list = [{"some.tld", "a reason"}, {"other.tld", "another reason"}]
+      expected = ["some.tld", "other.tld"]
+
+      assert MRF.instance_list_from_tuples(list) == expected
+    end
+  end
+
   describe "describe/0" do
     test "it works as expected with noop policy" do
       clear_config([:mrf, :policies], [Pleroma.Web.ActivityPub.MRF.NoOpPolicy])
diff --git a/test/web/activity_pub/publisher_test.exs b/test/web/activity_pub/publisher_test.exs
index 3a9d9ce26..ed8bed719 100644
--- a/test/web/activity_pub/publisher_test.exs
+++ b/test/web/activity_pub/publisher_test.exs
@@ -271,7 +271,7 @@ defmodule Pleroma.Web.ActivityPub.PublisherTest do
                    Pleroma.Web.Federator.Publisher,
                    [:passthrough],
                    [] do
-      Config.put([:instance, :quarantined_instances], ["domain.com"])
+      Config.put([:instance, :quarantined_instances], [{"domain.com", "some reason"}])
 
       follower =
         insert(:user, %{
@@ -308,7 +308,7 @@ defmodule Pleroma.Web.ActivityPub.PublisherTest do
                    Pleroma.Web.Federator.Publisher,
                    [:passthrough],
                    [] do
-      Config.put([:instance, :quarantined_instances], ["somedomain.com"])
+      Config.put([:instance, :quarantined_instances], [{"somedomain.com", "some reason"}])
 
       follower =
         insert(:user, %{