diff --git a/app/src/main/java/pl/szczodrzynski/edziennik/data/api/Constants.kt b/app/src/main/java/pl/szczodrzynski/edziennik/data/api/Constants.kt
index 483d152f..67313e67 100644
--- a/app/src/main/java/pl/szczodrzynski/edziennik/data/api/Constants.kt
+++ b/app/src/main/java/pl/szczodrzynski/edziennik/data/api/Constants.kt
@@ -22,9 +22,9 @@ const val FAKE_LIBRUS_TOKEN = "https://librus.szkolny.eu/access_token.php"
 const val FAKE_LIBRUS_ACCOUNT = "/synergia_accounts_fresh.php?login="
 const val FAKE_LIBRUS_ACCOUNTS = "/synergia_accounts.php"
 
-val LIBRUS_USER_AGENT = "$SYSTEM_USER_AGENT LibrusMobileApp"
+val LIBRUS_USER_AGENT = "${SYSTEM_USER_AGENT}LibrusMobileApp"
 const val SYNERGIA_USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) Gecko/20100101 Firefox/62.0"
-const val LIBRUS_CLIENT_ID = "wmSyUMo8llDAs4y9tJVYY92oyZ6h4lAt7KCuy0Gv"
+const val LIBRUS_CLIENT_ID = "6XPsKf10LPz1nxgHQLcvZ1KM48DYzlBAhxipaXY8"
 const val LIBRUS_REDIRECT_URL = "http://localhost/bar"
 const val LIBRUS_AUTHORIZE_URL = "https://portal.librus.pl/oauth2/authorize?client_id=$LIBRUS_CLIENT_ID&redirect_uri=$LIBRUS_REDIRECT_URL&response_type=code"
 const val LIBRUS_LOGIN_URL = "https://portal.librus.pl/rodzina/login/action"
diff --git a/app/src/main/java/pl/szczodrzynski/edziennik/data/api/edziennik/librus/login/LibrusLoginPortal.kt b/app/src/main/java/pl/szczodrzynski/edziennik/data/api/edziennik/librus/login/LibrusLoginPortal.kt
index fa667dc6..e8e00950 100644
--- a/app/src/main/java/pl/szczodrzynski/edziennik/data/api/edziennik/librus/login/LibrusLoginPortal.kt
+++ b/app/src/main/java/pl/szczodrzynski/edziennik/data/api/edziennik/librus/login/LibrusLoginPortal.kt
@@ -63,23 +63,31 @@ class LibrusLoginPortal(val data: DataLibrus, val onSuccess: () -> Unit) {
                 .userAgent(LIBRUS_USER_AGENT)
                 .withClient(data.app.httpLazy)
                 .callback(object : TextCallbackHandler() {
-                    override fun onSuccess(json: String, response: Response) {
+                    override fun onSuccess(text: String, response: Response) {
                         val location = response.headers().get("Location")
                         if (location != null) {
                             val authMatcher = Pattern.compile("http://localhost/bar\\?code=([A-z0-9]+?)$", Pattern.DOTALL or Pattern.MULTILINE).matcher(location)
-                            if (authMatcher.find()) {
-                                accessToken(authMatcher.group(1), null)
-                            } else {
-                                authorize(location)
+                            when {
+                                authMatcher.find() -> {
+                                    accessToken(authMatcher.group(1), null)
+                                }
+                                location.contains("rejected_client") -> {
+                                    data.error(ApiError(TAG, ERROR_LOGIN_LIBRUS_PORTAL_INVALID_CLIENT_ID)
+                                            .withResponse(response)
+                                            .withApiResponse("Location: $location\n$text"))
+                                }
+                                else -> {
+                                    authorize(location)
+                                }
                             }
                         } else {
-                            val csrfMatcher = Pattern.compile("name=\"csrf-token\" content=\"([A-z0-9=+/\\-_]+?)\"", Pattern.DOTALL).matcher(json)
+                            val csrfMatcher = Pattern.compile("name=\"csrf-token\" content=\"([A-z0-9=+/\\-_]+?)\"", Pattern.DOTALL).matcher(text)
                             if (csrfMatcher.find()) {
                                 login(csrfMatcher.group(1))
                             } else {
                                 data.error(ApiError(TAG, ERROR_LOGIN_LIBRUS_PORTAL_CSRF_MISSING)
                                         .withResponse(response)
-                                        .withApiResponse(json))
+                                        .withApiResponse(text))
                             }
                         }
                     }
@@ -186,7 +194,7 @@ class LibrusLoginPortal(val data: DataLibrus, val onSuccess: () -> Unit) {
                     return
                 }
                 val error = if (response?.code() == 200) null else
-                    json.getString("hint")
+                    json.getString("hint") ?: json.getString("error")
                 error?.let { code ->
                     when (code) {
                         "Authorization code has expired" -> ERROR_LOGIN_LIBRUS_PORTAL_CODE_EXPIRED
@@ -197,11 +205,9 @@ class LibrusLoginPortal(val data: DataLibrus, val onSuccess: () -> Unit) {
                         "Check the `code` parameter" -> ERROR_LOGIN_LIBRUS_PORTAL_NO_CODE
                         "Check the `refresh_token` parameter" -> ERROR_LOGIN_LIBRUS_PORTAL_NO_REFRESH
                         "Check the `redirect_uri` parameter" -> ERROR_LOGIN_LIBRUS_PORTAL_NO_REDIRECT
-                        else -> when (json.getString("error")) {
-                            "unsupported_grant_type" -> ERROR_LOGIN_LIBRUS_PORTAL_UNSUPPORTED_GRANT
-                            "invalid_client" -> ERROR_LOGIN_LIBRUS_PORTAL_INVALID_CLIENT_ID
-                            else -> ERROR_LOGIN_LIBRUS_PORTAL_OTHER
-                        }
+                        "unsupported_grant_type" -> ERROR_LOGIN_LIBRUS_PORTAL_UNSUPPORTED_GRANT
+                        "invalid_client" -> ERROR_LOGIN_LIBRUS_PORTAL_INVALID_CLIENT_ID
+                        else -> ERROR_LOGIN_LIBRUS_PORTAL_OTHER
                     }.let { errorCode ->
                         data.error(ApiError(TAG, errorCode)
                                 .withApiResponse(json)
diff --git a/app/src/main/res/values/errors.xml b/app/src/main/res/values/errors.xml
index f9842e65..126300bd 100644
--- a/app/src/main/res/values/errors.xml
+++ b/app/src/main/res/values/errors.xml
@@ -252,7 +252,7 @@
     <string name="error_168_reason">ERROR_LOGIN_LIBRUS_PORTAL_NO_REFRESH</string>
     <string name="error_169_reason">ERROR_LOGIN_LIBRUS_PORTAL_NO_REDIRECT</string>
     <string name="error_170_reason">ERROR_LOGIN_LIBRUS_PORTAL_UNSUPPORTED_GRANT</string>
-    <string name="error_171_reason">ERROR_LOGIN_LIBRUS_PORTAL_INVALID_CLIENT_ID</string>
+    <string name="error_171_reason">Błędne ID klienta. Zgłoś błąd programiście oraz zaktualizuj aplikację.</string>
     <string name="error_172_reason">ERROR_LOGIN_LIBRUS_PORTAL_REFRESH_INVALID</string>
     <string name="error_173_reason">ERROR_LOGIN_LIBRUS_PORTAL_REFRESH_REVOKED</string>
     <string name="error_174_reason">ERROR_LIBRUS_SYNERGIA_OTHER</string>