diff --git a/watchtower-plugin/net/http.py b/watchtower-plugin/net/http.py
index d523c9a..c456855 100644
--- a/watchtower-plugin/net/http.py
+++ b/watchtower-plugin/net/http.py
@@ -62,15 +62,15 @@ def send_appointment(tower_id, tower, appointment_dict, signature):
     add_appointment_endpoint = f"{tower.get('netaddr')}/add_appointment"
     response = process_post_response(post_request(data, add_appointment_endpoint, tower_id))
 
-    signature = response.get("signature")
+    tower_signature = response.get("signature")
     # Check that the server signed the appointment as it should.
-    if not signature:
+    if not tower_signature:
         raise SignatureError("The response does not contain the signature of the appointment", signature=None)
 
-    rpk = Cryptographer.recover_pk(Appointment.from_dict(appointment_dict).serialize(), signature)
+    rpk = Cryptographer.recover_pk(Appointment.from_dict(appointment_dict).serialize(), tower_signature)
     if tower_id != Cryptographer.get_compressed_pk(rpk):
         raise SignatureError(
-            "The returned appointment's signature is invalid", tower_id=tower_id, rpk=rpk, signature=signature
+            "The returned appointment's signature is invalid", tower_id=tower_id, rpk=rpk, signature=tower_signature
         )
 
     return response
diff --git a/watchtower-plugin/tower_info.py b/watchtower-plugin/tower_info.py
index 8aa6b7a..7156dce 100644
--- a/watchtower-plugin/tower_info.py
+++ b/watchtower-plugin/tower_info.py
@@ -8,6 +8,7 @@ class TowerInfo:
         pending_appointments=None,
         invalid_appointments=None,
     ):
+
         self.netaddr = netaddr
         self.available_slots = available_slots
         self.status = status
diff --git a/watchtower-plugin/watchtower.py b/watchtower-plugin/watchtower.py
index dc24663..3a5c85e 100755
--- a/watchtower-plugin/watchtower.py
+++ b/watchtower-plugin/watchtower.py
@@ -69,7 +69,7 @@ class WTClient:
             else:
                 tower_info.pending_appointments.remove(list(data))
         if "invalid_appointment" in tower_update:
-            tower_info.pending_appointments.append(list(tower_update.get("invalid_appointment")))
+            tower_info.invalid_appointments.append(list(tower_update.get("invalid_appointment")))
 
         self.towers[tower_id] = tower_info.get_summary()
         self.db_manager.store_tower_record(tower_id, tower_info)
@@ -219,20 +219,25 @@ def get_tower_info(plugin, tower_id):
 
 @plugin.method("retrytower", desc="Retry to send pending appointment to an unreachable tower.")
 def retry_tower(plugin, tower_id):
+    response = None
+    plugin.wt_client.lock.acquire()
     tower = plugin.wt_client.towers.get(tower_id)
 
     if not tower:
-        return {"error": f"{tower_id} is not a registered tower"}
-    if tower.get("status") != "unreachable":
-        return {"error": f"{tower_id} is not unreachable"}
+        response = {"error": f"{tower_id} is not a registered tower"}
+    if tower.get("status") not in ["unreachable", "subscription error"]:
+        response = {"error": f"{tower_id} is not unreachable. {tower.get('status')}"}
     if not tower.get("pending_appointments"):
-        return {"error": f"{tower_id} does not have pending appointments"}
+        response = {"error": f"{tower_id} does not have pending appointments"}
 
-    message = f"Retrying tower {tower_id}"
-    plugin.log(message)
-    plugin.wt_client.retrier.temp_unreachable_towers.put(tower_id)
+    if not response:
+        response = f"Retrying tower {tower_id}"
+        plugin.log(response)
+        plugin.wt_client.towers[tower_id]["status"] = "temporarily unreachable"
+        plugin.wt_client.retrier.temp_unreachable_towers.put(tower_id)
 
-    return message
+    plugin.wt_client.lock.release()
+    return response
 
 
 @plugin.hook("commitment_revocation")
@@ -260,8 +265,10 @@ def on_commitment_revocation(plugin, **kwargs):
 
         try:
             if tower.get("status") == "reachable":
-                signature, available_slots = add_appointment(plugin, tower_id, tower, appointment.to_dict(), signature)
-                tower_update["appointment"] = (appointment.locator, signature)
+                tower_signature, available_slots = add_appointment(
+                    plugin, tower_id, tower, appointment.to_dict(), signature
+                )
+                tower_update["appointment"] = (appointment.locator, tower_signature)
                 tower_update["available_slots"] = available_slots
 
             else: