diff --git a/instagrapi/exceptions.py b/instagrapi/exceptions.py
index f3c37632..116f5e53 100644
--- a/instagrapi/exceptions.py
+++ b/instagrapi/exceptions.py
@@ -166,6 +166,9 @@ class ProxyAddressIsBlocked(PrivateError):
 class BadPassword(PrivateError):
     pass
 
+class BadCredentials(PrivateError):
+    pass
+
 
 class PleaseWaitFewMinutes(PrivateError):
     pass
diff --git a/instagrapi/mixins/auth.py b/instagrapi/mixins/auth.py
index e86a2b27..33f418bd 100644
--- a/instagrapi/mixins/auth.py
+++ b/instagrapi/mixins/auth.py
@@ -7,7 +7,7 @@
 import time
 import uuid
 from pathlib import Path
-from typing import Dict
+from typing import Dict, Union
 from uuid import uuid4
 
 import requests
@@ -15,6 +15,7 @@
 
 from instagrapi import config
 from instagrapi.exceptions import (
+    BadCredentials,
     ClientThrottledError,
     PleaseWaitFewMinutes,
     PrivateError,
@@ -372,8 +373,8 @@ def login_by_sessionid(self, sessionid: str) -> bool:
 
     def login(
         self,
-        username: str,
-        password: str,
+        username: Union[str, None] = None,
+        password: Union[str, None] = None,
         relogin: bool = False,
         verification_code: str = "",
     ) -> bool:
@@ -396,8 +397,14 @@ def login(
         bool
             A boolean value
         """
-        self.username = username
-        self.password = password
+        
+        if not self.username or not self.password:
+            if username is None or password is None:
+                raise BadCredentials("Both username and password must be provided.")
+
+            self.username = username
+            self.password = password
+
         if relogin:
             self.authorization_data = {}
             self.private.headers.pop("Authorization", None)
@@ -416,7 +423,7 @@ def login(
             self.logger.warning("Ignore 429: Continue login")
             # The instagram application ignores this error
             # and continues to log in (repeat this behavior)
-        enc_password = self.password_encrypt(password)
+        enc_password = self.password_encrypt(self.password)
         data = {
             "jazoest": generate_jazoest(self.phone_id),
             "country_codes": '[{"country_code":"%d","source":["default"]}]'
diff --git a/tests.py b/tests.py
index c8f1589f..6f8e06a3 100644
--- a/tests.py
+++ b/tests.py
@@ -8,7 +8,7 @@
 from pathlib import Path
 
 from instagrapi import Client
-from instagrapi.exceptions import DirectThreadNotFound
+from instagrapi.exceptions import BadCredentials, DirectThreadNotFound, ProxyAddressIsBlocked, BadPassword
 from instagrapi.story import StoryBuilder
 from instagrapi.types import (
     Account,
@@ -105,12 +105,21 @@ class FakeClientTestCase(BaseClientMixin, unittest.TestCase):
 
     def test_login(self):
         try:
-            self.cl.login(ACCOUNT_USERNAME, "fakepassword")
-        except Exception as e:
+            self.cl.login(ACCOUNT_USERNAME, ACCOUNT_PASSWORD)
+        except (ProxyAddressIsBlocked, BadPassword) as e:
             self.assertEqual(
-                str(e), "The username you entered doesn't appear to belong to an account. Please check your username and try again."
+                str(e), "The password you entered is incorrect. Please try again. If you are sure that the password is correct, then change your IP address, because it is added to the blacklist of the Instagram Server"
             )
 
+        try:
+            is_auth = self.cl.login()
+            self.assertEqual(is_auth, True)
+        except BadCredentials as e:
+            self.assertEqual(str(e), "Both username and password must be provided.")
+        except ProxyAddressIsBlocked as e:
+            self.assertEqual(
+                str(e), "Instagram has blocked your IP address, use a quality proxy provider (not free, not shared)"
+            )
 
 class ClientPrivateTestCase(BaseClientMixin, unittest.TestCase):
     cl = None