diff --git a/CHANGELOG b/CHANGELOG
index 42f8394..66868ee 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,7 @@
+3.0.0 2020-08-19
+
+Use human-readable deny reason in plugin response.
+
 2.0.5 2019-04-19
 
 Initial release on GitHub.
diff --git a/MANIFEST b/MANIFEST
index 00c1a65..807046f 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -1,8 +1,8 @@
 name: SPS_RADIUS
 description: RADIUS (RSA) Multi-Factor Authentication plugin
-version: 2.0.5
+version: 3.0.0
 type: aa
-api: 1.1
+api: 1.6
 entry_point: main.py
 author_name: One Identity PAM Integration Team
 author_email: QDL.QBU-OI.RD.Safeguard.Integration@oneidentity.com
diff --git a/Pipfile b/Pipfile
index 5061c9c..4e96e60 100644
--- a/Pipfile
+++ b/Pipfile
@@ -3,7 +3,7 @@ pyrad = "*"
 
 [dev-packages]
 pyrad = "*"
-oneidentity-safeguard-sessions-plugin-sdk = "~=1.1.0"
+oneidentity-safeguard-sessions-plugin-sdk = "~=1.6.0"
 
 [requires]
 python_version = "3.6"
diff --git a/lib/plugin.py b/lib/plugin.py
index afb736a..188cda1 100644
--- a/lib/plugin.py
+++ b/lib/plugin.py
@@ -23,7 +23,8 @@
 from re import sub
 from socket import error as socket_error
 
-from safeguard.sessions.plugin import AAPlugin, AAResponse
+from safeguard.sessions.plugin import AAPlugin
+from safeguard.sessions.plugin.plugin_response import DenyReasons, AAResponse
 from pyrad.packet import AccessReject, AccessAccept, AccessChallenge
 
 from .radius import RadiusClient
@@ -60,22 +61,23 @@ def do_authenticate(self):
             radrep = radcli.authenticate(username=radius_username, password=self.mfa_password, state=prev_state)
         except TimeoutError:
             self.logger.error("Network timeout while talking to RADIUS server.")
-            return AAResponse.deny()
+            return AAResponse.deny(deny_reason=DenyReasons().backend_service_error)
         except socket_error as ex:
             self.logger.error("Network error while talking to RADIUS server: %s", ex)
-            return AAResponse.deny()
+            return AAResponse.deny(deny_reason=DenyReasons().communication_error)
         except Exception as ex:
-            self.logger.error("An exception of type %s occured. Arguments:\n%s", type(ex).__name__, ex.args)
+            self.logger.error(
+                "An exception of type %s occured. Arguments:\n%s", type(ex).__name__, ex.args,
+            )
             self.logger.debug("Exception details follow.", exc_info=ex)
             return AAResponse.deny()
 
         if radrep.code == AccessAccept:
             self.logger.info("RADIUS authentication was successful!")
             return AAResponse.accept()
-
         elif radrep.code == AccessReject:
             self.logger.info("RADIUS authentication was rejected!")
-            return AAResponse.deny()
+            return AAResponse.deny(deny_reason=DenyReasons().authentication_failure)
         elif radrep.code == AccessChallenge:
             self.logger.info("RADIUS challenge received")
             challenge = sub("\x00", "", "".join(radrep["Reply-Message"][0]))
diff --git a/lib/tests/unit/test_plugin.py b/lib/tests/unit/test_plugin.py
index d4b928f..e94f1a7 100644
--- a/lib/tests/unit/test_plugin.py
+++ b/lib/tests/unit/test_plugin.py
@@ -74,24 +74,23 @@ def fake_plugin_context(monkeypatch):
             monkeypatch.setitem(os.environ, "EPHEMERAL_PLUGIN_STATE_DIRECTORY", ephemeral_dir)
             yield
 
-
 def provide_get_radius_username_cases():
     yield {
-        "params": {"gateway_user": "gwuser", "key_value_pairs": {}, "target_username": "tguser"},
+        "params": {"gateway_user": "gwuser", "key_value_pairs": {}, "server_username": "srvuser"},
         "expected": "gwuser",
     }
-    yield {"params": {"gateway_user": None, "key_value_pairs": {}, "target_username": "tguser"}, "expected": "tguser"}
-    yield {"params": {"gateway_user": None, "key_value_pairs": {}, "target_username": None}, "expected": None}
+    yield {"params": {"gateway_user": None, "key_value_pairs": {}, "server_username": "srvuser"}, "expected": "srvuser"}
+    yield {"params": {"gateway_user": None, "key_value_pairs": {}, "server_username": None}, "expected": None}
     yield {
         "params": {
             "gateway_user": "gwuser",
             "key_value_pairs": {"radius_username": "radiususer", "ru": "ruuser"},
-            "target_username": "tguser",
+            "server_username": "srvuser",
         },
         "expected": "radiususer",
     }
     yield {
-        "params": {"gateway_user": "gwuser", "key_value_pairs": {"ru": "ruuser"}, "target_username": "tguser"},
+        "params": {"gateway_user": "gwuser", "key_value_pairs": {"ru": "ruuser"}, "server_username": "srvuser"},
         "expected": "ruuser",
     }
 
@@ -101,8 +100,7 @@ def test_get_radius_username(tc):
     def check_tc(params, expected):
         config = ""
         plugin = Plugin(config)
-        plugin.authenticate(**(enrich_params_with_mandatory_keys(params)))
-        print(plugin.cookie)
+        plugin.authenticate(**enrich_params_with_mandatory_keys(params))
         assert plugin.cookie.get("mfa_identity") == expected
 
     check_tc(**tc)
@@ -122,24 +120,25 @@ def check_tc(params, expected):
 
     check_tc(**tc)
 
-
 def enrich_params_with_mandatory_keys(params):
     connection_parameters = {
+        "cookie": {},
+        "session_cookie": {},
         "session_id": "",
-        "protocol": "",
+        "protocol": "SSH",
         "connection_name": "",
         "client_ip": "",
         "client_port": "",
-        "gateway_user": "",
-        "target_username": "",
-        "key_value_pairs": {},
-        "cookie": {},
-        "session_cookie": {},
+        "client_hostname": "",
+        "gateway_user": None,
+        "gateway_domain": None,
+        "server_username": None,
+        "server_domain": None,
+        "key_value_pairs": {}
     }
     connection_parameters.update(params)
     return connection_parameters
 
-
 def provide_get_radius_password_cases():
     yield {"params": {"key_value_pairs": {}}, "expected": None}
     yield {"params": {"key_value_pairs": {}}, "expected": None}
@@ -193,7 +192,7 @@ def test_authenticate_with_only_target_user():
             dict(
                 cookie={},
                 client_ip="1.2.3.4",
-                target_username="the_username",
+                server_username="the_username",
                 key_value_pairs={"radius_password": "the_password"},
             )
         )