Error message when updating

[Alain Aupeix]

Hi,

on a Xubuntu 16.04, no problem
on a Xubuntu 20.04, when apt update:
Ign :7 http://ppa.launchpad.net/tmate.io/archive/ubuntu focal InRelease Err :9 http://ppa.launchpad.net/tmate.io/archive/ubuntu focal Release 404 Not Found [IP : 2001:67c:1560:8008::19 80]
I notice that in http://ppa.launchpad.net/tmate.io/archive/ubuntu/dists/, the last distrib is devel. The next distribs are missing.
Is-it normal ?
Is there a way to bypass this error

Thanks
A+