diff --git a/modules/cmso/par/pages.py b/modules/cmso/par/pages.py
index 39608ab8bcf2116c410684baf015c48e38576c98..155bc0892a3047f9bd85cae06065c8ad9106c949 100644
--- a/modules/cmso/par/pages.py
+++ b/modules/cmso/par/pages.py
@@ -26,6 +26,7 @@
 
 from collections import OrderedDict
 
+from weboob.exceptions import BrowserUnavailable
 from weboob.browser.pages import HTMLPage, JsonPage, RawPage, LoggedPage, pagination
 from weboob.browser.elements import DictElement, ItemElement, TableElement, SkipItem, method
 from weboob.browser.filters.standard import CleanText, Upper, Date, Regexp, Format, CleanDecimal, Filter, Env, Slugify, Field
@@ -334,6 +335,13 @@ def next_page(self):
                 return requests.Request('POST', data=json.dumps(data), headers={'Content-Type': 'application/json'})
 
         def parse(self, el):
+            exception = Dict('exception', default=None)(self)
+            if exception:
+                message = exception.get('message', '')
+                assert 'SERVICE_INDISPONIBLE' in message, 'Unknown error in history page: "%s"' % message
+                # The error message is a stack trace so we do not
+                # send it.
+                raise BrowserUnavailable()
             # Key only if coming
             key = Env('key', default=None)(self)
             if key: