How welcome and leave messages work

Welcome (and leave) messages are configured on the dashboard's Welcome module — a channel, a message, and an optional image.

Placeholders

The message can include %user% (mentions them), %username% (their name, no ping), %server%, and %membercount% — typed anywhere in the title or body, filled in when it's actually posted.

It isn't posting

Check the module is switched on and a channel is selected.
Make sure Iridex can see and post in that channel.
A server-wide setting in Discord ("suppress @everyone and role mentions", or a slow mode on the channel) can occasionally interfere — try a different channel to isolate it.

Still stuck? Ask in the support server.