diff --git a/passwork_client/modules/api_client.py b/passwork_client/modules/api_client.py
index 7d22602..2f29292 100644
--- a/passwork_client/modules/api_client.py
+++ b/passwork_client/modules/api_client.py
@@ -55,7 +55,10 @@ def call(self, method: str, endpoint: str, payload: dict | None = None, headers:
 
     def _process_response(self, response):
         """Process API response and handle errors."""
-        data = response.json()
+        try:
+            data = response.json()
+        except json.JSONDecodeError:
+            raise PassworkError(f"Response not in JSON format. Text: {response.text}")
         result = data
 
         if data and isinstance(data, dict):