Push notification problem with pubsub.chatsecure.cat - prosody 0.11.9 (SASL EXTERNAL failed) #1250

Hi everybody,

After many attempts and a deep search on similar problem, I would really appreciate some help.
I am running an XMPP server on prosody (v0.11.9) and my clients on chatsecure app never received offline push notification.
Based on the server log, the push notifications are well activated :
Push notifications enabled for xxx@MY_DOMAIN.cat/chatsecure79578 (pubsub.chatsecure.org)

But when a message is sent to account connected to the chatsecure app (and the app is closed), I have :

Oct 02 14:55:57 MY_DOMAIN.cat:cloud_notify debug Invoking cloud handle_notify_request() for offline stanza Oct 02 14:55:57 MY_DOMAIN.cat:cloud_notify debug Sending important push notification for nicolas@MY_DOMAIN.cat to pubsub.chatsecure.org (A52799A4-EA42-4F4D-A818-C9C7388399EF) Oct 02 14:55:57 s2sout55e892bfa4f0 debug First attempt to connect to pubsub.chatsecure.org, starting with SRV lookup... Oct 02 14:55:57 adns debug Records for _xmpp-server._tcp.pubsub.chatsecure.org. not in cache, sending query (thread: 0x55e892d0f8b0)... Oct 02 14:55:57 MY_DOMAIN.cat:cloud_notify debug Sending important push notification for nicolas@MY_DOMAIN.cat to pubsub.chatsecure.org (5D6D0D0D-210C-4F77-8ECC-8C44CF52BA51) Oct 02 14:55:57 s2sout55e892bfa4f0 debug trying to send over unauthed s2sout to pubsub.chatsecure.org Oct 02 14:55:57 adns debug Reply for _xmpp-server._tcp.pubsub.chatsecure.org. (thread: 0x55e892d0f8b0) Oct 02 14:55:57 s2sout55e892bfa4f0 debug pubsub.chatsecure.org has SRV records, handling... Oct 02 14:55:57 s2sout55e892bfa4f0 debug Best record found, will connect to pubsub.chatsecure.org.:5269 Oct 02 14:55:57 adns debug Records for pubsub.chatsecure.org. not in cache, sending query (thread: 0x55e892c61390)... Oct 02 14:55:57 adns debug Reply for pubsub.chatsecure.org. (thread: 0x55e892c61390) Oct 02 14:55:57 s2sout55e892bfa4f0 debug DNS reply for pubsub.chatsecure.org. gives us 45.55.5.246 Oct 02 14:55:57 s2sout55e892bfa4f0 debug Beginning new connection attempt to pubsub.chatsecure.org ([45.55.5.246]:5269) Oct 02 14:55:58 s2sout55e892bfa4f0 debug Sending[s2sout_unauthed]: <stream:stream to='pubsub.chatsecure.org' xml:lang='en' version='1.0' xmlns:db='jabber:server:dialback' xmlns:stream='http://etherx.jabber.org/streams' xmlns='jabber:server' from='MY_DOMAIN.cat'> Oct 02 14:55:58 MY_DOMAIN.cat:tls debug pubsub.chatsecure.org is offering TLS, taking up the offer... Oct 02 14:55:59 s2sout55e892bfa4f0 debug Sending[s2sout_unauthed]: <stream:stream to='pubsub.chatsecure.org' xml:lang='en' version='1.0' xmlns:db='jabber:server:dialback' xmlns:stream='http://etherx.jabber.org/streams' xmlns='jabber:server' from='MY_DOMAIN.cat'> Oct 02 14:55:59 x509 debug Cert dNSName pubsub.chatsecure.org matched hostname Oct 02 14:55:59 MY_DOMAIN.cat:saslauth debug Initiating SASL EXTERNAL with pubsub.chatsecure.org Oct 02 14:55:59 MY_DOMAIN.cat:saslauth debug SASL EXTERNAL failed, falling back to dialback Oct 02 14:55:59 s2sout55e892bfa4f0 debug Sending[s2sout_unauthed]: <db:result to='pubsub.chatsecure.org' from='MY_DOMAIN.cat'> Oct 02 14:55:59 socket debug server.lua: client 45.55.5.246:clientport read error: closed Oct 02 14:55:59 s2sout55e892bfa4f0 debug s2s disconnected: MY_DOMAIN.cat->pubsub.chatsecure.org (closed) Oct 02 14:55:59 s2sout55e892bfa4f0 debug Destroying outgoing session MY_DOMAIN.cat->pubsub.chatsecure.org: closed Oct 02 14:55:59 s2sout55e892bfa4f0 info Sending error replies for 2 queued stanzas because of failed outgoing connection to pubsub.chatsecure.org Oct 02 14:55:59 stanzarouter debug Received[s2sin]: <iq to='MY_DOMAIN.cat' type='error' id='2c99f7318acfd37ab3f02abc4bdfe1ea6dc5b5075d9199750a97a4829bf6ede8' from='pubsub.chatsecure.org'> Oct 02 14:55:59 MY_DOMAIN.cat:cloud_notify info Got error of type 'cancel' (remote-server-not-found) for identifier 'pubsub.chatsecure.org<A52799A4-EA42-4F4D-A818-C9C7388399EF': error count for this identifier is now at 1 Oct 02 14:55:59 stanzarouter debug Received[s2sin]: <iq to='MY_DOMAIN.cat' type='error' id='9b4151632d0ff06bc73bb4abfe27456b6f4fa61ff129d78b36ce27755dd710b0' from='pubsub.chatsecure.org'> Oct 02 14:55:59 MY_DOMAIN.cat:cloud_notify info Got error of type 'cancel' (remote-server-not-found) for identifier 'pubsub.chatsecure.org<5D6D0D0D-210C-4F77-8ECC-8C44CF52BA51': error count for this identifier is now at 3

I use Let's Encrypt certificates and s2s_secure_auth is true.
In addition, I managed to activate the SASL authebtification when doing the same with pubsub.tigase.org

Thank you very much for the future help
Regards
DL