@Nik_V Thank you so much. Following your suggestions, I managed to make jigasi join as a hidden user with the TR icon being displayed instead of a new user. I assume that it is joining as an authenticated user on.
I added ALLOW_NON_SECURE (ALWAYS_TRUST_MODE_ENABLED was enabled already by default).
However, the CC button is still not calling the transcriber and I am trying to find the reason, it still behaves like before with no response nor error message on the js console or on the logs. I changed the jigasi user so it matches the behavior on beta environment. (email@example.com)
BTW, I had to comment the following setting:
Because it was giving the error message that I posted before:
org.jivesoftware.smack.SmackException: No supported and enabled SASL Mechanism provided by server. Server announced mechanisms: . Registered SASL mechanisms with Smack: [SASL Mech: GSSAPI, Prio: 100, SASL Mech: SCRAM-SHA-1-PLUS, Prio: 100, SASL Mech: SCRAM-SHA-1, Prio: 110, SASL Mech: DIGEST-MD5, Prio: 200, SASL Mech: CRAM-MD5, Prio: 300, SASL Mech: PLAIN, Prio: 400, SASL Mech: X-OAUTH2, Prio: 410, SASL Mech: EXTERNAL, Prio: 500, SASL Mech: ANONYMOUS, Prio: 500]. Enabled SASL mechanisms for this connection: [ANONYMOUS]. Blacklisted SASL mechanisms: [SCRAM-SHA-1-PLUS].