diff --git a/lib/pleroma/instances/instance.ex b/lib/pleroma/instances/instance.ex
index fb0b9d7f0..620544134 100644
--- a/lib/pleroma/instances/instance.ex
+++ b/lib/pleroma/instances/instance.ex
@@ -92,9 +92,20 @@ defmodule Pleroma.Instances.Instance do
   def reachable?(url_or_host) when is_binary(url_or_host), do: true
 
   def set_reachable(url_or_host) when is_binary(url_or_host) do
-    %Instance{host: host(url_or_host)}
-    |> changeset(%{unreachable_since: nil})
-    |> Repo.insert(on_conflict: {:replace, [:unreachable_since]}, conflict_target: :host)
+    host = host(url_or_host)
+
+    result =
+      %Instance{host: host}
+      |> changeset(%{unreachable_since: nil})
+      |> Repo.insert(on_conflict: {:replace, [:unreachable_since]}, conflict_target: :host)
+
+    # Delete any existing reachability testing jobs for this instance
+    Oban.Job
+    |> Ecto.Query.where(worker: "Pleroma.Workers.ReachabilityWorker")
+    |> Ecto.Query.where([j], j.args["domain"] == ^host)
+    |> Oban.delete_all_jobs()
+
+    result
   end
 
   def set_reachable(_), do: {:error, nil}
diff --git a/test/pleroma/instances/instance_test.exs b/test/pleroma/instances/instance_test.exs
index ed536c55c..354ba139a 100644
--- a/test/pleroma/instances/instance_test.exs
+++ b/test/pleroma/instances/instance_test.exs
@@ -27,6 +27,32 @@ defmodule Pleroma.Instances.InstanceTest do
       assert {:ok, instance} = Instance.set_reachable(instance.host)
       refute instance.unreachable_since
     end
+
+    test "cancels all ReachabilityWorker jobs for the domain" do
+      domain = "cancelme.example.org"
+      insert(:instance, host: domain, unreachable_since: NaiveDateTime.utc_now())
+
+      # Insert a ReachabilityWorker job for this domain, scheduled 5 minutes in the future
+      scheduled_at = DateTime.add(DateTime.utc_now(), 300, :second)
+
+      {:ok, job} =
+        Pleroma.Workers.ReachabilityWorker.new(
+          %{"domain" => domain, "phase" => "phase_1min", "attempt" => 1},
+          scheduled_at: scheduled_at
+        )
+        |> Oban.insert()
+
+      # Ensure the job is present
+      job = Pleroma.Repo.get(Oban.Job, job.id)
+      assert job
+
+      # Call set_reachable, which should delete the job
+      assert {:ok, _} = Instance.set_reachable(domain)
+
+      # Reload the job and assert it is deleted
+      job = Pleroma.Repo.get(Oban.Job, job.id)
+      refute job
+    end
   end
 
   describe "set_unreachable/1" do