diff --git a/server/routers/newt/error.ts b/server/routers/newt/error.ts
new file mode 100644
index 000000000..d2ab8937c
--- /dev/null
+++ b/server/routers/newt/error.ts
@@ -0,0 +1,24 @@
+import { sendToClient } from "#dynamic/routers/ws";
+
+// Error codes for registration failures
+export const NewtErrorCodes = {
+    NO_AVAILABLE_SUBNET: {
+        code: "NO_AVAILABLE_SUBNET",
+        message:
+            "No available subnet could be assigned to this site on its exit node. Please contact your administrator to increase the available address space for this exit node's subnet."
+    }
+} as const;
+
+// Helper function to send registration error
+export async function sendNewtError(
+    error: (typeof NewtErrorCodes)[keyof typeof NewtErrorCodes],
+    newtId: string
+) {
+    sendToClient(newtId, {
+        type: "newt/error",
+        data: {
+            code: error.code,
+            message: error.message
+        }
+    });
+}
diff --git a/server/routers/newt/handleNewtRegisterMessage.ts b/server/routers/newt/handleNewtRegisterMessage.ts
index 7adc74a1b..43dee26f5 100644
--- a/server/routers/newt/handleNewtRegisterMessage.ts
+++ b/server/routers/newt/handleNewtRegisterMessage.ts
@@ -14,6 +14,7 @@ import { getUniqueSubnetForExitNode } from "@server/lib/exitNodes";
 import { fetchContainers } from "./dockerSocket";
 import { buildTargetConfigurationForNewtClient } from "./buildConfiguration";
 import { canCompress } from "@server/lib/clientVersionChecks";
+import { NewtErrorCodes, sendNewtError } from "./error";
 
 export const handleNewtRegisterMessage: MessageHandler = async (context) => {
     const { message, client, sendToClient } = context;
@@ -116,6 +117,7 @@ export const handleNewtRegisterMessage: MessageHandler = async (context) => {
             logger.error(
                 `No available subnets found for the new exit node id ${exitNodeId} and site id ${siteId}`
             );
+            sendNewtError(NewtErrorCodes.NO_AVAILABLE_SUBNET, newt.newtId);
             return;
         }
 
diff --git a/server/routers/olm/error.ts b/server/routers/olm/error.ts
index d9058a3f6..b0fd90993 100644
--- a/server/routers/olm/error.ts
+++ b/server/routers/olm/error.ts
@@ -94,6 +94,11 @@ export const OlmErrorCodes = {
     HOLEPUNCH_MISSING: {
         code: "HOLEPUNCH_MISSING",
         message: `Unable to coordinate client P2P connection. Please ensure your client can reach the server on UDP port ${udpPort} and try registering again.`
+    },
+    NO_AVAILABLE_SUBNET: {
+        code: "NO_AVAILABLE_SUBNET",
+        message:
+            "No available subnet could be assigned to this client on the selected exit node. Please contact your administrator to increase the available address space for this exit node's subnet."
     }
 } as const;
 
diff --git a/server/routers/olm/handleOlmRegisterMessage.ts b/server/routers/olm/handleOlmRegisterMessage.ts
index 693920950..988e68afd 100644
--- a/server/routers/olm/handleOlmRegisterMessage.ts
+++ b/server/routers/olm/handleOlmRegisterMessage.ts
@@ -347,6 +347,7 @@ export const handleOlmRegisterMessage: MessageHandler = async (context) => {
                 `[handleOlmRegisterMessage] No available subnets found for exit node id ${exitNodeId} and client id ${client.clientId}`,
                 { orgId: client.orgId, clientId: client.clientId }
             );
+            sendOlmError(OlmErrorCodes.NO_AVAILABLE_SUBNET, olm.olmId);
             return;
         }