diff --git a/pr_agent/git_providers/bitbucket_server_provider.py b/pr_agent/git_providers/bitbucket_server_provider.py
index 43cdad7c..f805d0c2 100644
--- a/pr_agent/git_providers/bitbucket_server_provider.py
+++ b/pr_agent/git_providers/bitbucket_server_provider.py
@@ -38,10 +38,39 @@ class BitbucketServerProvider(GitProvider):
         self.diff_files = None
         self.bitbucket_pull_request_api_url = pr_url
         self.bearer_token = get_settings().get("BITBUCKET_SERVER.BEARER_TOKEN", None)
-        self.bitbucket_server_url = self._parse_bitbucket_server(url=pr_url)
-        self.bitbucket_client = bitbucket_client or Bitbucket(url=self.bitbucket_server_url,
-                                                              token=get_settings().get("BITBUCKET_SERVER.BEARER_TOKEN",
-                                                                                       None))
+        # Get username and password from settings
+        username = get_settings().get("BITBUCKET_SERVER.USERNAME", None)
+        password = get_settings().get("BITBUCKET_SERVER.PASSWORD", None)
+        # If bitbucket_client is provided, try to extract the server URL from its configuration
+        if bitbucket_client:
+            self.bitbucket_client = bitbucket_client
+            try:
+                # Get the base URL from the existing client
+                self.bitbucket_server_url = bitbucket_client.url
+            except AttributeError:
+                # If we can't get the URL from the client, try parsing it from PR URL
+                self.bitbucket_server_url = self._parse_bitbucket_server(url=pr_url) if pr_url else None
+        else:
+            # Parse server URL from PR URL
+            self.bitbucket_server_url = self._parse_bitbucket_server(url=pr_url) if pr_url else None
+
+        # Validate the server URL unless we have a pre-configured client
+        if not bitbucket_client and not self.bitbucket_server_url:
+            raise ValueError("Invalid or missing Bitbucket Server URL parsed from PR URL.")
+
+        # If no client provided, create one with the appropriate authentication
+        if not bitbucket_client:
+            if self.bearer_token:
+                self.bitbucket_client = Bitbucket(
+                    url=self.bitbucket_server_url,
+                    token=self.bearer_token
+                )
+            else:
+                self.bitbucket_client = Bitbucket(
+                    url=self.bitbucket_server_url,
+                    username=username,
+                    password=password
+                )
         try:
             self.bitbucket_api_version = parse_version(self.bitbucket_client.get("rest/api/1.0/application-properties").get('version'))
         except Exception: