Unable to join matrix room

1

Trying to join https://riot.im/app/#/room/#asciinema:matrix.org I got

You were kicked from asciinema by @appservice-irc:matrix.org
Reason: IRC error on #asciinema: err_needreggednick
2

Still unable to join, is any update here?

3

You need to pay attention about activating your registration by confirming it via the instructions received by email, usually using appropriate IRC command with personally unique confirmation code, that also came with email:
/msg NickServ VERIFY REGISTER your-nickname confirmation-code

Then I was able to join without issues:
/join #asciinema

Although I used HexChat in first place to properly complete registration, activation, joining with channel. Then also Element could join with channel.

Also here is the guide how to participate IRC room using Matrix and its client Element.

4

https://riot.im/app/#/room/#asciinema:matrix.org is a matrix room, not IRC.