diff --git a/weboob/browser/exceptions.py b/weboob/browser/exceptions.py
index e134d29ae324223391e97f6d643335d41380263b..df4ea8f9b77fe06d5243b6dedbf12d028d96a8ed 100644
--- a/weboob/browser/exceptions.py
+++ b/weboob/browser/exceptions.py
@@ -63,6 +63,9 @@ def __init__(self, message='', next_try=None):
         if next_try is None:
             next_try = BrowserTooManyRequests.NEXT_24H
 
+        if not isinstance(next_try, datetime.datetime):
+            raise TypeError('next_try value should be a datetime.')
+
         self.next_try = next_try
 
     def __str__(self):