diff --git a/BTCPayServer.Tests/GreenfieldAPITests.cs b/BTCPayServer.Tests/GreenfieldAPITests.cs
index 3c6bdcc29..2dc9252a2 100644
--- a/BTCPayServer.Tests/GreenfieldAPITests.cs
+++ b/BTCPayServer.Tests/GreenfieldAPITests.cs
@@ -1795,14 +1795,11 @@ namespace BTCPayServer.Tests
             {
                 await nonAdminUserClient.GetStoreLightningNetworkPaymentMethod(nonAdminUser.StoreId, "BTC");
             });
-            await Assert.ThrowsAsync<GreenFieldValidationException>(async () =>
-            {
-                await nonAdminUserClient.UpdateStoreLightningNetworkPaymentMethod(nonAdminUser.StoreId, "BTC", new UpdateLightningNetworkPaymentMethodRequest()
+            await AssertPermissionError("btcpay.server.canuseinternallightningnode", () => nonAdminUserClient.UpdateStoreLightningNetworkPaymentMethod(nonAdminUser.StoreId, "BTC", new UpdateLightningNetworkPaymentMethodRequest()
                 {
                     Enabled = method.Enabled,
                     ConnectionString = method.ConnectionString
-                });
-            });
+                }));
 
             settings = await tester.PayTester.GetService<SettingsRepository>().GetSettingAsync<PoliciesSettings>();
             settings.AllowLightningInternalNodeForAll = true;
@@ -1813,6 +1810,36 @@ namespace BTCPayServer.Tests
                 Enabled = method.Enabled,
                 ConnectionString = method.ConnectionString
             });
+
+            // NonAdmin can't set to internal node in AllowLightningInternalNodeForAll is false, but can do other connection string
+            settings = (await tester.PayTester.GetService<SettingsRepository>().GetSettingAsync<PoliciesSettings>()) ?? new PoliciesSettings();
+            settings.AllowLightningInternalNodeForAll = false;
+            await tester.PayTester.GetService<SettingsRepository>().UpdateSetting(settings);
+            await nonAdminUserClient.UpdateStoreLightningNetworkPaymentMethod(nonAdminUser.StoreId, "BTC", new UpdateLightningNetworkPaymentMethodRequest()
+            {
+                Enabled = true,
+                ConnectionString = "type=clightning;server=tcp://8.8.8.8"
+            });
+            await AssertPermissionError("btcpay.server.canuseinternallightningnode", () => nonAdminUserClient.UpdateStoreLightningNetworkPaymentMethod(nonAdminUser.StoreId, "BTC", new UpdateLightningNetworkPaymentMethodRequest()
+            {
+                Enabled = true,
+                ConnectionString = "Internal Node"
+            }));
+            // NonAdmin add admin as owner of the store
+            await nonAdminUser.AddOwner(admin.UserId);
+            // Admin turn on Internal node
+            adminClient = await admin.CreateClient(Policies.CanModifyStoreSettings, Policies.CanUseInternalLightningNode);
+            var data = await adminClient.UpdateStoreLightningNetworkPaymentMethod(nonAdminUser.StoreId, "BTC", new UpdateLightningNetworkPaymentMethodRequest()
+            {
+                Enabled = method.Enabled,
+                ConnectionString = "Internal Node"
+            });
+            // Make sure that the nonAdmin can toggle enabled, ConnectionString unchanged.
+            await nonAdminUserClient.UpdateStoreLightningNetworkPaymentMethod(nonAdminUser.StoreId, "BTC", new UpdateLightningNetworkPaymentMethodRequest()
+            {
+                Enabled = !data.Enabled,
+                ConnectionString = "Internal Node"
+            });
         }
 
         [Fact(Timeout = 60 * 2 * 1000)]
diff --git a/BTCPayServer.Tests/TestAccount.cs b/BTCPayServer.Tests/TestAccount.cs
index 6e3846056..0abe095b5 100644
--- a/BTCPayServer.Tests/TestAccount.cs
+++ b/BTCPayServer.Tests/TestAccount.cs
@@ -526,5 +526,10 @@ retry:
             var repo = this.parent.PayTester.GetService<StoreRepository>();
             await repo.AddStoreUser(StoreId, userId, "Guest");
         }
+        public async Task AddOwner(string userId)
+        {
+            var repo = this.parent.PayTester.GetService<StoreRepository>();
+            await repo.AddStoreUser(StoreId, userId, "Owner");
+        }
     }
 }
diff --git a/BTCPayServer/Controllers/GreenField/StoreLightningNetworkPaymentMethodsController.cs b/BTCPayServer/Controllers/GreenField/StoreLightningNetworkPaymentMethodsController.cs
index 92e55366f..fc1f78e77 100644
--- a/BTCPayServer/Controllers/GreenField/StoreLightningNetworkPaymentMethodsController.cs
+++ b/BTCPayServer/Controllers/GreenField/StoreLightningNetworkPaymentMethodsController.cs
@@ -129,15 +129,16 @@ namespace BTCPayServer.Controllers.GreenField
                 return this.CreateValidationError(ModelState);
 
             LightningSupportedPaymentMethod? paymentMethod = null;
-            if (!string.IsNullOrEmpty(request!.ConnectionString))
+            var store = Store;
+            var storeBlob = store.GetStoreBlob();
+            var existing = GetExistingLightningLikePaymentMethod(_btcPayNetworkProvider, cryptoCode, store);
+            if (existing == null || existing.ConnectionString != request.ConnectionString)
             {
                 if (request.ConnectionString == LightningSupportedPaymentMethod.InternalNode)
                 {
                     if (!await CanUseInternalLightning())
                     {
-                        ModelState.AddModelError(nameof(request.ConnectionString),
-                            $"You are not authorized to use the internal lightning node");
-                        return this.CreateValidationError(ModelState);
+                        return this.CreateAPIPermissionError(Policies.CanUseInternalLightningNode, $"You are not authorized to use the internal lightning node. Either add '{Policies.CanUseInternalLightningNode}' to an API Key, or allow non-admin users to use the internal lightning node in the server settings.");
                     }
 
                     paymentMethod = new Payments.Lightning.LightningSupportedPaymentMethod()
@@ -176,9 +177,6 @@ namespace BTCPayServer.Controllers.GreenField
                     paymentMethod.SetLightningUrl(connectionString);
                 }
             }
-
-            var store = Store;
-            var storeBlob = store.GetStoreBlob();
             store.SetSupportedPaymentMethod(paymentMethodId, paymentMethod);
             storeBlob.SetExcluded(paymentMethodId, !request.Enabled);
             store.SetStoreBlob(storeBlob);