diff --git a/dags/common/exceptions.py b/dags/common/exceptions.py
new file mode 100644
index 0000000..199a119
--- /dev/null
+++ b/dags/common/exceptions.py
@@ -0,0 +1,10 @@
+class WrongInput(Exception):
+    def __init__(self, input, current_year):
+        super().__init__(
+            f"Wrong input. Input should be digits and in  range of 2004 to {current_year}: {input}"
+        )
+
+
+class DataFetchError(Exception):
+    def __init__(self, status_code, url):
+        super().__init__(f"Data fetch failure, status_code={status_code}, url={url}")
diff --git a/dags/open_access/gold_open_access_mechanisms.py b/dags/open_access/gold_open_access_mechanisms.py
index 3507a8e..c008b01 100644
--- a/dags/open_access/gold_open_access_mechanisms.py
+++ b/dags/open_access/gold_open_access_mechanisms.py
@@ -4,6 +4,7 @@
 import pendulum
 from airflow.decorators import dag, task
 from airflow.providers.postgres.operators.postgres import PostgresOperator
+from common.exceptions import DataFetchError
 from executor_config import kubernetes_executor_config
 
 
@@ -23,8 +24,14 @@ def fetch_data_task(query, **kwargs):
         )
         type_of_query = [*query][0]
         url = utils.get_url(f"{golden_access_base_query}+{query[type_of_query]}")
-        data = utils.get_data(url)
-        total = utils.get_total_results_count(data.text)
+        response = utils.get_data(url)
+        count = 1
+        while response.status_code == 502 and count != 10:
+            count = count + 1
+            response = utils.get_data(url)
+        if response.status_code != 200:
+            raise DataFetchError(url, response.status_code)
+        total = utils.get_total_results_count(response.text)
         return {type_of_query: total}
 
     @task(multiple_outputs=True, executor_config=kubernetes_executor_config)
diff --git a/dags/open_access/utils.py b/dags/open_access/utils.py
index 0c8955e..0bf334e 100644
--- a/dags/open_access/utils.py
+++ b/dags/open_access/utils.py
@@ -1,8 +1,10 @@
+import datetime
 import math
 import re
 
 import backoff
 import requests
+from common.exceptions import WrongInput
 from open_access.parsers import get_golden_access_records_ids
 
 
@@ -62,7 +64,15 @@ def get_total_results_count(data):
 
 
 @backoff.on_exception(
-    backoff.expo, requests.exceptions.ProxyError, max_time=120, max_tries=5
+    backoff.expo, requests.exceptions.ProxyError, max_time=1000, max_tries=10
 )
 def get_data(url):
     return requests.get(url)
+
+
+def check_year(year):
+    current_year = datetime.date.today().year
+    if type(year) == int:
+        if int(year) >= 2004 and int(year) <= current_year:
+            return year
+    raise WrongInput(year, current_year)