diff --git a/README.md b/README.md
index 4e0bc9a..fc66845 100644
--- a/README.md
+++ b/README.md
@@ -127,6 +127,8 @@ If you are not sure which encryption method to use, you can leave it empty or pa
 
 This function will throw a `LoginTimeoutException` when no match is found, since this is still a HTTP Time Out. This could caused by the wrong encryption method, but also by trying to connect to an inaccessible host.
 
+It will throw a `LoginRetryErrorException` when the router has locked logins after too many attempts. Wait for the lock to expire before trying again.
+
 ### Handle exceptions
 
 Some functions may cause an error when an attempt is made to execute it. These exceptions are thrown by the client and need to be [handled in your Python program](https://docs.python.org/3/tutorial/errors.html#handling-exceptions). Best practice is to catch some specific exceptions and handle them gracefully.
diff --git a/sagemcom_api/client.py b/sagemcom_api/client.py
index e2c6081..6c10ded 100644
--- a/sagemcom_api/client.py
+++ b/sagemcom_api/client.py
@@ -364,7 +364,11 @@ async def logout(self):
         self._request_id = -1
 
     async def get_encryption_method(self):
-        """Determine which encryption method to use for authentication and set it directly."""
+        """Determine which encryption method to use for authentication and set it directly.
+
+        :raises LoginRetryErrorException: the router has locked logins after too many attempts.
+            Probing further would only extend the lock, so detection stops here.
+        """
         for encryption_method in EncryptionMethod:
             try:
                 self.authentication_method = encryption_method
@@ -380,7 +384,6 @@ async def get_encryption_method(self):
             except (
                 LoginTimeoutException,
                 AuthenticationException,
-                LoginRetryErrorException,
             ):
                 pass
 
diff --git a/tests/conftest.py b/tests/conftest.py
index 5b39653..edf39a9 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -40,6 +40,12 @@ def login_auth_error_response() -> dict[str, Any]:
     return load_fixture("login_auth_error.json")
 
 
+@pytest.fixture
+def login_retry_error_response() -> dict[str, Any]:
+    """Mock response for a login locked after too many attempts."""
+    return load_fixture("login_retry_error.json")
+
+
 @pytest.fixture
 def login_invalid_session_response() -> dict[str, Any]:
     """Mock response for invalid session error."""
diff --git a/tests/fixtures/login_retry_error.json b/tests/fixtures/login_retry_error.json
new file mode 100644
index 0000000..f0e0697
--- /dev/null
+++ b/tests/fixtures/login_retry_error.json
@@ -0,0 +1,22 @@
+{
+  "reply": {
+    "uid": 0,
+    "id": 0,
+    "error": {
+      "code": 16777236,
+      "description": "XMO_REQUEST_ACTION_ERR"
+    },
+    "actions": [
+      {
+        "uid": 1,
+        "id": 0,
+        "error": {
+          "code": 16777224,
+          "description": "XMO_LOGIN_RETRY_ERR"
+        },
+        "callbacks": []
+      }
+    ],
+    "events": []
+  }
+}
diff --git a/tests/unit/test_encryption_method.py b/tests/unit/test_encryption_method.py
new file mode 100644
index 0000000..32ec1d8
--- /dev/null
+++ b/tests/unit/test_encryption_method.py
@@ -0,0 +1,31 @@
+"""Tests for automatic encryption method detection."""
+
+import pytest
+
+from sagemcom_api.client import SagemcomClient
+from sagemcom_api.enums import EncryptionMethod
+from sagemcom_api.exceptions import LoginRetryErrorException
+
+
+@pytest.mark.asyncio
+async def test_detection_stops_when_router_locks_login(mock_session_factory, login_retry_error_response):
+    """XMO_LOGIN_RETRY_ERR means the router has locked logins; probing further only extends the lock."""
+    mock_session = mock_session_factory([login_retry_error_response] * 3)
+    client = SagemcomClient("192.168.1.1", "admin", "admin", session=mock_session)
+
+    with pytest.raises(LoginRetryErrorException):
+        await client.get_encryption_method()
+
+    assert mock_session.post.call_count == 1
+
+
+@pytest.mark.asyncio
+async def test_detection_moves_on_after_authentication_error(mock_session_factory, login_auth_error_response, login_success_response):
+    """A plain authentication error still means "wrong method", so the next method is tried."""
+    mock_session = mock_session_factory([login_auth_error_response, login_success_response])
+    client = SagemcomClient("192.168.1.1", "admin", "admin", session=mock_session)
+
+    method = await client.get_encryption_method()
+
+    assert method == EncryptionMethod.MD5_NONCE
+    assert mock_session.post.call_count == 2