stop sending chatstates when remote server doesn't respond anymore. Don't acknoledge error message receipes. Fixes #4064

src/common/connection_handlers.py

@@ -2004,7 +2004,7 @@ class ConnectionHandlers(ConnectionVcard, ConnectionBytestream, ConnectionDisco,
 		if msg.getTag('request', namespace=common.xmpp.NS_RECEIPTS) \
 		and gajim.config.get_per('accounts', self.name,
 		'answer_receipts') and ((contact and contact.sub \
-		not in (u'to', u'none')) or gc_contact):
+		not in (u'to', u'none')) or gc_contact) and mtype != 'error':
 			receipt = common.xmpp.Message(to=frm, typ='chat')
 			receipt.setID(msg.getID())
 			receipt.setTag('received',

src/gajim.py

@@ -892,6 +892,11 @@ class Interface:
 		jids = full_jid_with_resource.split('/', 1)
 		jid = jids[0]
 
+		if array[1] == '503':
+			# If we get server-not-found error, stop sending chatstates
+			for contact in gajim.contacts.get_contacts(account, jid):
+				contact.composing_xep = False
+
 		session = None
 		if len(array) > 5:
 			session = array[5]