diff --git a/.github/workflows/docker.yml b/.github/workflows/docker.yml
index 864c0fd..0ae6e14 100644
--- a/.github/workflows/docker.yml
+++ b/.github/workflows/docker.yml
@@ -59,7 +59,7 @@ jobs:
 
     - name: Build
       env:
-        DOCKER_USER: ${{ vars.DOCKER_HUB_USERNAME || 'USER' }}
+        DOCKER_USER: ${{ vars.DOCKER_HUB_USERNAME || 'user' }}
         BUILD_NR: ${{ github.run_number }}
         PLATFORM: ${{ matrix.platforms }}
         VERSION: ${{ needs.Setup.outputs.version }}
@@ -79,7 +79,7 @@ jobs:
 
     - name: Test
       env:
-        DOCKER_USER: ${{ vars.DOCKER_HUB_USERNAME || 'USER' }}
+        DOCKER_USER: ${{ vars.DOCKER_HUB_USERNAME || 'user' }}
         BUILD_NR: ${{ github.run_number }}
         PLATFORM: ${{ matrix.platforms }}
         VERSION: ${{ needs.Setup.outputs.version }}
@@ -99,13 +99,13 @@ jobs:
       if: github.event_name == 'release'
       uses: docker/login-action@v2
       with:
-        username: ${{ vars.DOCKER_HUB_USERNAME || 'USER' }}
+        username: ${{ vars.DOCKER_HUB_USERNAME || 'user' }}
         password: ${{ secrets.DOCKER_HUB_DEPLOY_KEY }}
 
     - name: Push Images
       if: github.event_name == 'release'
       env:
-        DOCKER_USER: ${{ vars.DOCKER_HUB_USERNAME || 'USER' }}
+        DOCKER_USER: ${{ vars.DOCKER_HUB_USERNAME || 'user' }}
         BUILD_NR: ${{ github.run_number }}
         PLATFORM: ${{ matrix.platforms }}
         VERSION: ${{ needs.Setup.outputs.version }}
@@ -135,12 +135,12 @@ jobs:
     - name: Login to Docker Hub
       uses: docker/login-action@v2
       with:
-        username: ${{ vars.DOCKER_HUB_USERNAME || 'USER' }}
+        username: ${{ vars.DOCKER_HUB_USERNAME || 'user' }}
         password: ${{ secrets.DOCKER_HUB_DEPLOY_KEY }}
 
     - name: Create and push shared manifest
       env:
-        DOCKER_USER: ${{ vars.DOCKER_HUB_USERNAME || 'USER' }}
+        DOCKER_USER: ${{ vars.DOCKER_HUB_USERNAME || 'user' }}
         BUILD_NR: ${{ github.run_number }}
         VERSION: ${{ needs.Setup.outputs.version }}
       run: |
diff --git a/porkbun_ddns/porkbun_ddns.py b/porkbun_ddns/porkbun_ddns.py
index 438d61f..2306554 100644
--- a/porkbun_ddns/porkbun_ddns.py
+++ b/porkbun_ddns/porkbun_ddns.py
@@ -85,8 +85,16 @@ def get_public_ips(self) -> list:
             else:
                 if self.ipv4:
                     try:
-                        public_ips.append(urllib.request.urlopen(
-                            'https://v4.ident.me').read().decode('utf8'))
+                        response = urllib.request.urlopen('https://v4.ident.me')
+                        if response.getcode() == 200:
+                            public_ips.append(response.read().decode('utf-8'))
+                        else:
+                            logger.warning("Failed to retrieve IPv4 Address! HTTP status code: {}".format(response.code()))
+                            alternative_response = urllib.request.urlopen('https://api.ipify.org/')
+                            if alternative_response.getcode() == 200:
+                                public_ips.append(alternative_response.read().decode('utf-8'))
+                            else:
+                                logger.warning("Failed to retrieve IPv4 Address! HTTP status code: {}".format(response.code()))
                     except URLError:
                         logger.warning("Can't reach IPv4 Address! Check IPv4 connectivity!")
                 if self.ipv6:
diff --git a/porkbun_ddns/test/test_porkbun_ddns.py b/porkbun_ddns/test/test_porkbun_ddns.py
index ff51f24..76ab52f 100644
--- a/porkbun_ddns/test/test_porkbun_ddns.py
+++ b/porkbun_ddns/test/test_porkbun_ddns.py
@@ -1,5 +1,5 @@
 import unittest
-from unittest.mock import patch
+from unittest.mock import patch, MagicMock
 from ..porkbun_ddns import PorkbunDDNS, PorkbunDDNS_Error
 import logging
 
@@ -159,6 +159,23 @@ def test_record_overwrite_alias_and_cname(self, mocker=None):
                               'INFO:porkbun_ddns:Creating AAAA-Record for my-domain.local with content: '
                               '0000:0000:0000:0000:0000:0000:0000:0001, Status: SUCCESS'])
 
+    @patch('urllib.request.urlopen')
+    def test_urlopen_returns_500(self, mock_urlopen):
+        # Set up the mock to return a response with status code 500
+        mock_response = MagicMock()
+        mock_response.getcode.return_value = 500
+        mock_urlopen.return_value = mock_response
+
+        # Instantiate your class or call the method that uses urllib.request.urlopen()
+        porkbun_ddns = PorkbunDDNS(valid_config, domain='example.com', ipv4=True, ipv6=False)
+
+        # Now when you call the method that uses urllib.request.urlopen(), it will get the mocked response
+        with self.assertRaises(PorkbunDDNS_Error) as context:
+            porkbun_ddns.get_public_ips()
+
+        # Verify that the exception has the expected error message
+        self.assertEqual(str(context.exception), 'Failed to obtain IP Addresses!')
+
 
 if __name__ == '__main__':
     unittest.main()