Hello Jos
This happens because mysql-apt-config doesn't recognize Ubuntu 26.04's codename yet, so it silently writes a broken/disabled repo line, and apt falls back to the default Ubuntu repo for mysql-server without erroring.
To Fix thsi:
1) Check cat /etc/apt/sources.list.d/mysql.list, if the deb line is missing or commented out, that confirms it.
2) Manually write the repo line, using the closest supported LTS codename instead of 26.04:
echo "deb
http://repo.mysql.com/apt/ubuntu/ jammy mysql-8.0" | sudo tee /etc/apt/sources.list.d/mysql.list
3) Re-import the key if needed:
wget
https://dev.mysql.com/get/mysql-apt-config_0.8.29-1_all.deb
sudo dpkg -i mysql-apt-config_0.8.29-1_all.deb
When prompted for OS version, manually pick the nearest supported release instead of letting it auto-detect.
4) Run sudo apt update and confirm mysql.com actually shows up in the fetched sources before installing.
Until mysql-apt-config adds explicit 26.04 support, pinning to the previous LTS codename in the repo line is the reliable workaround.
Regards,
Herrick
Technical support Engineer, Accuweb.cloud