Djoot

On my OpenSuse server I had to add :Z after /data in the bind, dont know if it applies to your setup, but it is easy to test and see if it works

Are you running with subtitles? I had the same issue and it disappeared when I turned off subtitles

MQTT is just a messaging protocol, it’s mostly used for iot purposes like you mention, but can in theory be used for any kind of project.

Never used ejabberd, but one of their selling points are multiprotocol support, so it’s not so weird to support a multipurpose standardized messaging protocol.