--- a/sat/plugins/plugin_xep_0060.py	Sun Apr 14 08:21:51 2019 +0200
+++ b/sat/plugins/plugin_xep_0060.py	Sun Apr 14 08:21:51 2019 +0200
@@ -611,6 +611,7 @@
             )
             # we have no MAM data here, so we add None
             d.addCallback(lambda data: data + (None,))
+            d.addErrback(sat_defer.stanza2NotFound)
             d.addTimeout(TIMEOUT, reactor)
         else:
             # if mam is requested, we have to do a totally different query

--- a/sat/tools/sat_defer.py	Sun Apr 14 08:21:51 2019 +0200
+++ b/sat/tools/sat_defer.py	Sun Apr 14 08:21:51 2019 +0200
@@ -26,6 +26,7 @@
 from twisted.internet import defer
 from twisted.internet import error as internet_error
 from twisted.internet import reactor
+from twisted.words.protocols.jabber import error as jabber_error
 from twisted.python import failure
 from sat.core.constants import Const as C
 from sat.memory import memory
@@ -34,6 +35,14 @@
 KEY_NEXT = "next_defer"
 
 
+def stanza2NotFound(failure_):
+    """Convert item-not-found StanzaError to exceptions.NotFound"""
+    failure_.trap(jabber_error.StanzaError)
+    if failure_.value.condition == u'item-not-found':
+        raise exceptions.NotFound(failure_.value.text or failure_.value.condition)
+    return failure_
+
+
 class DelayedDeferred(object):
     """A Deferred-like which is launched after a delay"""