diff --git a/src/gibby/client.py b/src/gibby/client.py
index 80d612a..94ce40b 100644
--- a/src/gibby/client.py
+++ b/src/gibby/client.py
@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import json
+import logging
 
 import httpx
 
@@ -10,6 +11,8 @@ from gibby.settings import Settings
 
 MODELS_URL = "https://chatgpt.com/backend-api/codex/models"
 
+logger = logging.getLogger(__name__)
+
 
 class OpenAIAPIError(RuntimeError):
     def __init__(
@@ -104,7 +107,17 @@ class OpenAIClient:
         return parse_usage_payload(await self.fetch_usage_payload(access_token))
 
     async def validate_token(self, access_token: str) -> bool:
-        response = await self.http_client.get(MODELS_URL, headers=self._headers(access_token))
+        response = await self.http_client.get(
+            MODELS_URL,
+            headers=self._headers(access_token),
+            params={"client_version": "2.3.9"},
+        )
+        if response.status_code != 200:
+            logger.warning(
+                "token validation failed: status=%s body=%s",
+                response.status_code,
+                _extract_error_text(response),
+            )
         return response.status_code == 200
 
     @staticmethod
diff --git a/src/gibby/manager.py b/src/gibby/manager.py
index fbd9c85..5897bd0 100644
--- a/src/gibby/manager.py
+++ b/src/gibby/manager.py
@@ -29,10 +29,29 @@ class AccountManager:
             while True:
                 state = self.store.load()
                 if not state.accounts:
+                    logger.error("no usable account available: no accounts in state file")
                     raise NoUsableAccountError("No usable account available")
 
                 account = await self._select_account(state)
                 if account is None:
+                    logger.error(
+                        "no usable account available: active_account=%s accounts=%s",
+                        state.active_account,
+                        [
+                            {
+                                "email": item.email,
+                                "disabled": item.disabled,
+                                "usage_checked_at": item.usage_checked_at,
+                                "primary": item.usage.primary_window.used_percent
+                                if item.usage and item.usage.primary_window
+                                else None,
+                                "secondary": item.usage.secondary_window.used_percent
+                                if item.usage and item.usage.secondary_window
+                                else None,
+                            }
+                            for item in state.accounts
+                        ],
+                    )
                     raise NoUsableAccountError("No usable account available")
 
                 state = self.store.load()