Multitoolbox cant install Docker in Ubuntu 20.04.4

[noelj-osoftag]

Hello. So i tried everything to install docker with the Multitoolbox 7.1 using Ubuntu 20.04 and 20.04.4 (latest). tried with multiple ways to install all updates on ubuntu server and the result was all the time that im first getting this error:
The repository 'file:/cdrom focal Release' no longer has a Release file.

1. and then multibox says: Docker was not installed
2. user xxx is member of docker.
   I always fix the 'crdom' issue with putting a # in GNU Nano infront of the file but still the multibox cant install docker.

[noelj-osoftag]

@XK4MiLX could you help me here or ask other developers?

[noelj-osoftag]

I got it working by bypassing the update to the latest Ubuntu! it is still annoying that the latest version doesnt support the multittolbox. maybe make a discord warning?

[stanchiam]

if not wrong, it is due to mongodb installation not supported after 20.04